a long term solution would be to pull the asyncio extension out of the .ext/ namespace so that the imports would be from sqlalchemy.asyncio import create_async_engine and from sqlalchemy.orm.asycnio import AsyncSession. Then sqlalchemy.ext.asyncio would be a compatibility shim that isn't needed, the same way Declarative started out as sqlalchemy.ext.

That's not something we can do in the 2.0 series however since we are very late in the series and 2.1 is very close to beta releases (nor would i introduce __getattr__() trickery in a 2.0.26 release).

Originally posted by @zzzeek in #12971 (comment)