A lot of writers try to set their own rules, but according to the best, you need limitations to be creative. Just like you would play sports with rules. That rulebook is Poetics.
It's the kind of book that's so information dense that you have to read it slowly. Summaries are often as long as the book itself.
There's some aging in there. Notably the concept of hamartia has changed from "mistake" to "sin" over a few hundred years. Good stories were all tragedy back then, where a noble person makes a mistake. And the audience is fearful because if this superior person can make mistakes, what about me?
Since Christianity, the philosophy has been that everyone makes mistakes, but repenting for it saves you from tragedy. And more popular now is a reversal. Some tries to slay a monster, but the monster is too perfect. But eventually the monster suffers from hamartia (missing the mark, making human sins) and the hero exploits that to win.
Besides drama, the book also covers actual poetry and music, both of which have their own limitations, but that part was all Greek to me.