I began using the standard "tutorial" style and started cringing when I saw the official template [1] place all CRUD operations in a single file (I've been doing Rails and Spring for a while before) and the way dependencies where managed... let's just say I wasn't feeling very comfortable.
Then came the SQLModel problems. The author pushes it very hard in the FastAPI docs (which imho are terrible because when I'm looking for docs I want that, documentation, not a fancy tutorial) but as an ORM (yes I know its a layer on top of SQLAlchemy) it doesn't even support polymorphic models and the community even has contributed PRs that have gone months without any review (is it even maintained anymore? I honestly can't tell).
I guess I'm the only one to blame for choosing FastAPI to build a big project but after having used it quite a lot (and also read its code because again, docs are extremely poor) I wouldn't recommend it for anything serious. Sure, if you want to build a quick CRUD then go ahead and use SQLModel and FastAPI, but keep in mind that its not built for complex applications (at least not without requiring you to write a framework on top, like I've unfortunately done).
So yeah, a big thank you to the author of this post because I will migrate to Litestar as soon as I wake up tomorrow.