well the sotapanna have these gains
"Monks, there are these six rewards in realizing the fruit of
stream-entry. Which six? One is certain of the true Dhamma. One is not
subject to falling back. There is no suffering over what has had a
limit placed on it. [1] One is endowed with uncommon knowledge. [2]
One rightly sees cause, along with causally-originated phenomena.
https://www.accesstoinsight.org/tipitaka/an/an06/an06.097.than.html
the arahant has the special knowledge of destruction of the taints
"With his mind thus concentrated, purified, and bright, unblemished,
free from defects, pliant, malleable, steady, and attained to
imperturbability, the monk directs and inclines it to the knowledge of
the ending of the mental fermentations. He discerns, as it is actually
present, that 'This is stress... This is the origination of stress...
This is the cessation of stress... This is the way leading to the
cessation of stress... These are fermentations... This is the
origination of fermentations... This is the cessation of
fermentations... This is the way leading to the cessation of
fermentations.' His heart, thus knowing, thus seeing, is released from
the fermentation of sensuality, the fermentation of becoming, the
fermentation of ignorance. With release, there is the knowledge,
'Released.' He discerns that 'Birth is ended, the holy life fulfilled,
the task done. There is nothing further for this world.'
https://www.accesstoinsight.org/tipitaka/mn/mn.060.than.html
same thing here
"Thus, monks, Ignorance is the supporting condition for the (kamma-)
formations [etc. to] Birth. Birth for Suffering, Suffering for Faith,
Faith for Joy, Joy for Delight, Delight for Tranquillity, Tranquillity
for Happiness, Happiness for Concentration, Concentration for
Knowledge-and-vision-of-things-as-they-are,
Knowledge-and-vision-of-things-as-they-are for Disenchantment,
Disenchantment for Dispassion, Dispassion for Liberation, Liberation
for Knowledge of the destruction of the cankers."
https://www.accesstoinsight.org/tipitaka/sn/sn12/sn12.023x.wlsh.html
for the intermediate case of non returner, those people know about the ''passion for the five strings of sensuality'', but they suck at knowing how dukkha are vinanna and namarupa,
"In the same way, I tell you, is the nutriment of physical food to be
regarded. When physical food is comprehended, passion for the five
strings of sensuality is comprehended. When passion for the five
strings of sensuality is comprehended, there is no fetter bound by
which a disciple of the noble ones would come back again to this
world.
https://www.accesstoinsight.org/tipitaka/sn/sn12/sn12.063.than.html
