4 years later, in 2025, it still seems there is no solution for shared table multitenancy in SQLAlchemy. The last commit of MultiAlchemy is now 9 years ago.

I opened another thread for my issue where I started to implement it on my own. Maybe it helps a bit. However, I am not sure if I get to some really useful result... SQLAlchemy multitenancy (shared table)

Maybe somebody found/programmed a solution in the meantime?