I think there won't be any radical changes during betas, they probably end up in the next release.
Radical no, that would require to add JIT which is planned for 3.12 AFAIK. But there are two performance improvements after release of first beta already: https://speed.python.org/
I've been following what PRs the faster-cpython people merge and it's been nothing on the beta branch, I think. For example this PR is not getting merged, it seems. https://github.com/python/cpython/pull/93379
That's only 7 days ago. I might be wrong, but I think Python betas are not like RCs -- they are changing things, not just polishing.