It seems to me that a big part of the problem is that Cython feels entitled to use arbitrary CPython internals. Another part is that there doesn't seem to be any Cython maintainer interested in communicating with the core devs who are changing those CPython internals. We have to resort to creating issues in the Cython tracker and wait weeks before someone responds, and often not in a supportive way.

I am fully aware that Cython is an important tool in our ecosystem. But before I agree that we should roll back things "because it breaks Cython" I would like to see a lot more participation in CPython's development by Cython developers. (Who are they even? I only know "scoder" -- who else can speak authoritatively on behalf of Cython?)

During a beta cycle I would see the roles reversed. But until late May we are still working on alphas. If Cython wants to wait until beta 1 that's fine, but then their input on the design of CPython changes is necessarily much more limited.