I feel you are mixing totally different libraries and blaming SQLAlchemy for it. I use SQLAlchemy a lot and go through its documentation. I use it with FastAPI or other micro-frameworks.

But I need SQLAlchemy to really work with ... SQL! And it is solid at that. The glue libraries between bigger ones like SQLAlchemy and Flask usually are less maintained and have less eyeballs on them. These are weaker points IMHO, not SQLAlchemy.