You haven’t read much Abhidharma if “comprehensible” is how you would describe Theravada.

Not saying anything is wrong with Theravada. Entire cultures are built on its principles. But it takes a surface-level glance to think of it as something simple and easy to understand.

Zen though, most of the teachings are about pedagogical methods rather than doctrine. That’s why it sounds weird to westerners who think of “religion” as dusty old books and priests who tell you what to do/think.

Zen teachings literally tell you “Don’t cling to fixed ideas. Don’t seek answers from some external authority figure.” Everything they teach is about guiding you to internalize those things. It’s about showing, not telling.

So expecting it to “make sense” in the lens of “just let me read a book that will tell me what to believe” is already starting from the wrong foot.