This is more a system design question than a programming one. It might be on-topic over at Software Engineering - check their Help Centre to see. — Toby Speight 39 secs ago

It's not clear from your post what is framework layer, but in general it is a good practice to separate database layer from business logic, and to separate those two from API. It seems this is what you are trying to achieve. I'm not sure if your question fits well for stackoverflow, and maybe it could be addressed better on softwareengineering.stackexchange.com ? As a bonus, I would think about separation of concerns design principle here, and I would ask the question: does the service layer need to know details of SQLAlchemy? — Konrad Talik 16 secs ago

I've posted the question on softwareengineering.stackexchange.com. Thanks — Альберт Александров 47 secs ago

See softwareengineering.stackexchange.com/questions/409856/… — Rui Jarimba 5 secs ago