Commit refactoring can be really hard work however. Basically you do something like taking N random commits and convert these into M logical ones - where each one delivers incremental value and builds upon the other.

For some types of work it is easy, N=M: you were able to do high quality value adding atomic commits for the whole PR without rework.

For other types N >> M. This can happen when trying different approaches to a hard problem. I suppose research type work could always be considered a POC and the actual implementation could be a kind of cleanroom re-implementation of the POC but there isn't always time for such things and (again) the PR is far more important than the commits that built up to it - particularly if the resultant code is of equal quality. Note that I am not advocating for long running branches here - trunk based development is generally better provided it doesn't over incentivize teams to avoid hard problems (but that is a topic for another day).

This is why I think git should include the PR as a first class concept. For simple N=M type work, 1 PR should generally be 1 commit. Why not, after all, make the PR small and easy to review when you can? For harder N >> M type work, you get one PR with many commits that one can dig into if necessary.