FWIW, I've only looked at the lru_cache() code.  Someone should go through all the PyModule_GetState calls to see if they are on a critical path.  AFAICT a huge number of these changes were applied without regard to whether or not they occurred on an existing fast path.

This is a considerable number of clock cycles for a type lookup that used to be almost cost free.  Whether it is high or low impact greatly depends on whether the surrounding code was doing a lot of work or very little work.  In thin functions, the incremental costs will be higher.