Hi Larry,
Can you give us a status update for your PEP 649? I don't recall reading anything about it in the past few weeks. I am super excited about this solution to the problem (even if there are a few issues to work through) and I think it will provide better backwards compatibility than the current plan for Python 3.10 (PEP 563, from __future__ import annotations, causing all annotations to be stringified).
If we don't get this into 3.10, we'd have a much more complicated transition. There are only two more alphas before 3.10b1 gets released! And we'd have to get this approved by the Steering Council, which can take a few weeks (cut them some slack, they have a big backlog). Fortunately you already have an implementation that can be landed quickly once the PEP is accepted.