Back in the day people recited but a few discourses, there were no schools nor walls of text to choose from; ip there were no Abhidhamma books, no Vinayas and yet people had more attainments, were making better progress.
That time was more favorable. If you could go back in time even to years like 377BC, you would see a lot of Ariya, probably fully attained but no Mahayana texts or Theravadin Abhidhamma books.
So how essential do you think they are?
Abhidhamma is basically a different expression of the same meaning as the Sutta. It's expression is supposedly rightly inferred from the meaning & expression of pali discourses which were memorized. It is agreeable to some and disagreeable to those of other persuasions about Sutta meaning.
Afaik Theravada school forms around 300BC and their texts aren't done written down until something like a couples of hundred years later.
Mahayana texts are introduced around that time and and are also deemed heretical by some who hold that those early Mahayana texts disagree with pali discourses held as true and agreeable in meaning & expression.
It looks like the monks were inevitably developing personal commentary and ways of doing things all along, explaining things in their own words and according to their understanding. Grouping accotdingly. Therefore it was common to see people who analyzed popular notions and practices within the big schools all along.
After the 1st century a lot of supposedly correct commentary, polularizations, classifications, lore and whatnot is being written by more and more people and it has not stopped.
The quality of expression and meaning was corrupted in the process because it's hard to explain the Dhamma better than Buddha did, it is therefore non understanding of Buddha's expression that directly or indirectly prompts the adding to, complementing, the making of popularizations, simplifying, censoring or otherwise changing the expression and or meaning.
In the Sutta some people grasped the Dhamma after a verse of how Dhamma as it was generally presented by The Buddha and his direct disciples;
"Aggivessana, the Blessed One disciplines his disciples in this way; this part of the Blessed One's instruction is generally presented to his disciples: 'Form is inconstant. Feeling is inconstant. Perception is inconstant. Fabrications are inconstant. Consciousness is inconstant. Form is not-self. Feeling is not-self. Perception is not-self. Fabrications are not-self. Consciousness is not-self. All fabrications are inconstant. All phenomena are not-self.' This, Aggivessana, is the way in which the Blessed One disciplines his disciples; this part of the Blessed One's instruction is generally presented to his disciples."
It can be said that the full penetration of the meaning of this expression is the objective. Some people need more clarification than others and some won't get it even after a lifetime.
Of course in times of the Buddha people became followers not understanding the Dhamma and grew in and into it's understanding.
So the Buddha also taught the Dhamma in all essential ways including practices conducive to the development of knowledge.
It is generally accepted that the Pali texts are the things Buddha actually said to people he met.
The main collections of pali discourses are generally accepted as texts from the period of True Dhamma, a period of 500 years proclaimed in the Sutta, a period before the arising of Counterfeit Dhamma.
Imo a great teacher would proclaim the dhamma, so that it clallenges one's views, rouses effort and settles doubt.
Without a teacher one has a lot of text for a teacher, so it is about becoming familiar with what is out there to separate true texts from fake dhamma.
When one has confidence in a text as being the real deal one can learn and think about it. Eventually one would understand the essentials of the doctrine as it is generally explained. Then one may come to agreement or reject the idea.
Eventually one would probably fine the true texts and come to agreement with the doctrine, understanding the meaning and expression of true Dhamma.
At that point one can effectively scrutinize the expression in all text, from Abhidhamma to Buddha quotes on the internet. In the Sutta it is explained as the ability to distinguish what is rightly spoken.
Reading the Sutta is like listening in on coversations, trying to understand exactly what is talked about and emulating the training.
Imo best sorting is according to the theme one is preocupied with, studyin it in dwtail as to the meaning & use of every word in the system of expression found therein.
As i see it, one will end up reading and refering to some discourses more than others, drawing parallels and rearranging them to extract a cohesive expression of meaning. Some of it you will inevitably memorize and theorize about.
Many discourses are useful because they are a support for what should be inferred from another discourse. Many discourses are useful because they refute what should not be inferred from another discourse. Many discourses are wordplay in that they beautify the expression, illucidate the meaning and or are inspiring.
All this one will see in the process. Learning from people on the internet is a different can of worms and i would advice against it lest the texts that are known as true are being recited.
As long as one stays intellectually honest it should work out very well.
In short, a lot of people read a whole lot of fake dhamma.
Here's a thread with some discourses i listed as of particular interest few years ago;
https://dhammawheel.com/viewtopic.php?f=13&t=29180&start=15#p419374
