The various realms in the Pali suttas include psychological examples therefore they obviously apply psychologically. For example:

The question: "Are Therevada's cosmology and the Mahanaya's sutras physically plasusible?" is impossible to answer & outside of the scope of Buddha-Dhamma, which is described as:

This Dhamma is to be seen here & now, immediate, inviting inspection, pertinent, to be realized/verified by the observant for themselves. MN 38

SN 35.23 states:

The eye & forms, ear & sounds, nose & aromas, tongue & flavors, body & tactile sensations, mind & mind objects. This, monks, is called the All. Anyone who would say, 'Repudiating this All, I will describe another,' if questioned on what exactly might be the grounds for his statement, would be unable to explain and would be put to grief. Why? Because it lies beyond range.

The various realms in the Pali suttas include psychological examples therefore obviously this is all that can be known. For example:

It is just within this fathom-long body, with its perception & intellect, that I declare that there is the world, the origination of the world, the cessation of the world and the path of practice leading to the cessation of the world. AN 4.45

Intention, I tell you, is kamma. Intending, one does kamma by way of body, speech, & intellect. And what is the cause by which kamma comes into play? Contact is the cause by which kamma comes into play. And what is the diversity in kamma? There is kamma to be experienced in hell (niraya), kamma to be experienced in the realm of animals ( tiracchānayoni), kamma to be experienced in the realm of the hungry shades (pettivisaya), kamma to be experienced in the human world (manussaloka), kamma to be experienced in the world of the devas (devaloka). This is called the diversity in kamma. AN 6.63

I have seen, bhikkhus, the hell named ‘Contact’s Sixfold Base.’ There whatever form one sees with the eye is undesirable, never desirable; unlovely, never lovely; disagreeable, never agreeable. Whatever sound one hears with the ear … Whatever odour one smells with the nose … Whatever taste one savours with the tongue … Whatever tactile object one feels with the body … Whatever mental phenomenon one cognizes with the mind is undesirable, never desirable; unlovely, never lovely; disagreeable, never agreeable. SN 35.135

Here, Udayi, the bhikkhu secluded from sensual desires and thoughts of demerit abides in the first jhana: Overcoming thoughts and thought processes and the mind in one point internally appeased, without thoughts and thought processes abides in the second jhana. Again with equanimity to joy and detachment, feeling pleasant with the body too, abides in the third jhana. To this the noble ones say abiding in pleasantness with equanimity. Udayi, this is the course of actions, for realising the world of only pleasant feelings (ekantasukhassa lokassa).MN 79

Bhikkhus, there are three kinds of persons found existing in the world. What three? (1) “Here, bhikkhus, some person generates afflictive bodily activities, afflictive verbal activities, and afflictive mental activities. In consequence, he reappears (upapajjati) in an afflictive world. When he reappears in an afflictive world, afflictive contacts touch him. Being touched by afflictive contacts, he feels afflictive feelings, exclusively painful, as in the case of hell-beings. (2) “Someone else generates unafflictive bodily activities, unafflictive verbal activities, and unafflictive mental activities. In consequence, he reappears in an unafflictive world. When he reappears in an unafflictive world, unafflictive contacts touch him. Being touched by unafflictive contacts, he feels unafflictive feelings, exclusively pleasant, as in the case of the devas of refulgent glory. (3) “Still another generates bodily activities that are both afflictive and unafflictive, verbal activities that are both afflictive and unafflictive, and mental activities that are both afflictive and unafflictive. In consequence, he reappears in a world that is both afflictive and unafflictive. When he reappears in a world that is both afflictive and unafflictive, both afflictive and unafflictive contacts touch him. Being touched by both afflictive and unafflictive contacts, he feels both afflictive and unafflictive feelings, mingled pleasure and pain, as in the case of human beings, some devas, and some beings in the lower worlds. These, bhikkhus, are the three kinds of persons found existing in the world. AN 3.23

Sensual desire… ill-will (anger)… sloth & drowsiness… restlessness & anxiety… uncertainty is an obstacle, a hindrance that overwhelms the mind and weakens wisdom… when a monk has not abandoned these five obstacles… for him to understand what is for his own benefit, to understand what is for the benefit of others, to understand what is for the benefit of both, to realize a superior human (manussa) state (dhammā), a truly noble distinction in knowledge & vision: that is impossible. AN 5.51

Sooner, I say, would that blind turtle, coming to the surface once every hundred years, insert its neck into that yoke with a single hole than the fool who has gone once to the nether world would regain the human state. For what reason? Because here, bhikkhus, there is no conduct guided by the Dhamma, no righteous conduct, no wholesome activity, no meritorious activity. Here there prevails mutual devouring, the devouring of the weak. For what reason? Because, bhikkhus, they have not seen the Four Noble Truths. What four? The noble truth of suffering … the noble truth of the way leading to the cessation of suffering. SN 56.47

Bhikkhus, a god, a human or any other good state would not be evident from actions born of greed, hate and delusion. Yet, bhikkhus, from actions born of greed, hate and delusion a hellish being, an animal birth a ghostly birth or some other bad state would be evident. AN 6.39

Bhikkhus, these two bright principles protect the world. What are the two? Shame and fear of wrongdoing. If, bhikkhus, these two bright principles did not protect the world, there would not be discerned respect for mother or maternal aunt or maternal uncle’s wife or a teacher’s wife or the wives of other honored persons, and the world would have fallen into promiscuity, as with goats, sheep, chickens, pigs, dogs, and jackals. But as these two bright principles protect the world, there is discerned respect for mother… and the wives of other honored persons. AN 2.9

Now on that occasion the wanderers of other persuasions had come together in a gathering and were sitting, discussing many kinds of bestial (animal) topics, making a great noise and racket. AN 10.93

Beings (sattā) are few who, when they pass away from the animal realm (tiracchā­na­yoniyā) are reborn (paccājāyanti) among humans (manussesu)… those beings are more numerous are reborn in hell…. For what reason? They have not realised the Four Noble Truths. SN 56.102 to 131

It is just within this fathom-long body, with its perception & intellect, that I declare that there is the world, the origination of the world, the cessation of the world and the path of practice leading to the cessation of the world. AN 4.45

Intention, I tell you, is kamma. Intending, one does kamma by way of body, speech, & intellect. And what is the cause by which kamma comes into play? Sense contact is the cause by which kamma comes into play. And what is the diversity in kamma? There is kamma to be experienced in hell (niraya), kamma to be experienced in the realm of animals ( tiracchānayoni), kamma to be experienced in the realm of the hungry shades (pettivisaya), kamma to be experienced in the human world (manussaloka), kamma to be experienced in the world of the devas (devaloka). This is called the diversity in kamma. AN 6.63

I have seen, bhikkhus, the hell named ‘Contact’s Sixfold Base.’ There whatever form one sees with the eye is undesirable, never desirable; unlovely, never lovely; disagreeable, never agreeable. Whatever sound one hears with the ear … Whatever odour one smells with the nose … Whatever taste one savours with the tongue … Whatever tactile object one feels with the body … Whatever mental phenomenon one cognizes with the mind is undesirable, never desirable; unlovely, never lovely; disagreeable, never agreeable. SN 35.135

Here, Udayi, the bhikkhu secluded from sensual desires and thoughts of demerit abides in the first jhana: Overcoming thoughts and thought processes and the mind in one point internally appeased, without thoughts and thought processes abides in the second jhana. Again with equanimity to joy and detachment, feeling pleasant with the body too, abides in the third jhana. To this the noble ones say abiding in pleasantness with equanimity. Udayi, this is the course of actions, for realising the world of only pleasant feelings (ekantasukhassa lokassa).MN 79

Bhikkhus, there are three kinds of persons found existing in the world. What three? (1) “Here, bhikkhus, some person generates afflictive bodily activities, afflictive verbal activities, and afflictive mental activities. In consequence, he reappears (upapajjati) in an afflictive world. When he reappears in an afflictive world, afflictive contacts touch him. Being touched by afflictive contacts, he feels afflictive feelings, exclusively painful, as in the case of hell-beings. (2) “Someone else generates unafflictive bodily activities, unafflictive verbal activities, and unafflictive mental activities. In consequence, he reappears in an unafflictive world. When he reappears in an unafflictive world, unafflictive contacts touch him. Being touched by unafflictive contacts, he feels unafflictive feelings, exclusively pleasant, as in the case of the gods of refulgent glory. (3) “Still another generates bodily activities that are both afflictive and unafflictive, verbal activities that are both afflictive and unafflictive, and mental activities that are both afflictive and unafflictive. In consequence, he reappears in a world that is both afflictive and unafflictive. When he reappears in a world that is both afflictive and unafflictive, both afflictive and unafflictive contacts touch him. Being touched by both afflictive and unafflictive contacts, he feels both afflictive and unafflictive feelings, mingled pleasure and pain, as in the case of human beings, some devas, and some beings in the lower worlds. These, bhikkhus, are the three kinds of persons found existing in the world. AN 3.23

Sensual desire… ill-will (anger)… sloth & drowsiness… restlessness & anxiety… uncertainty is an obstacle, a hindrance that overwhelms the mind and weakens wisdom… when a monk has not abandoned these five obstacles… for him to understand what is for his own benefit, to understand what is for the benefit of others, to understand what is for the benefit of both, to realize a superior human (manussa) state (dhammā), a truly noble distinction in knowledge & vision: that is impossible. AN 5.51

Sooner, I say, would that blind turtle, coming to the surface once every hundred years, insert its neck into that yoke with a single hole than the fool who has gone once to the nether world would regain the human state. For what reason? Because here, bhikkhus, there is no conduct guided by the Dhamma, no righteous conduct, no wholesome activity, no meritorious activity. Here there prevails mutual devouring, the devouring of the weak. For what reason? Because, bhikkhus, they have not seen the Four Noble Truths. What four? The noble truth of suffering … the noble truth of the way leading to the cessation of suffering. SN 56.47

Bhikkhus, a god, a human or any other good state would not be evident from actions born of greed, hate and delusion. Yet, bhikkhus, from actions born of greed, hate and delusion a hellish being, an animal birth a ghostly birth or some other bad state would be evident. AN 6.39

Bhikkhus, these two bright principles protect the world. What are the two? Shame and fear of wrongdoing. If, bhikkhus, these two bright principles did not protect the world, there would not be discerned respect for mother or maternal aunt or maternal uncle’s wife or a teacher’s wife or the wives of other honored persons, and the world would have fallen into promiscuity, as with goats, sheep, chickens, pigs, dogs, and jackals. But as these two bright principles protect the world, there is discerned respect for mother… and the wives of other honored persons. AN 2.9

Now on that occasion the wanderers of other persuasions had come together in a gathering and were sitting, discussing many kinds of bestial (animal) topics, making a great noise and racket. AN 10.93

Beings (sattā) are few who, when they pass away from the animal realm (tiracchā­na­yoniyā) are reborn (paccājāyanti) among humans (manussesu)… those beings are more numerous are reborn in hell…. For what reason? They have not realised the Four Noble Truths. SN 56.102 to 131