I have found myself arranging PR's on github in sequence, for the exact sort of use case OP talks about. (Each PR might have more than one commit, so it's not exactly the same practice). And been frustrated that Github's interface does not make it very easy to make the sequence apparent or have good DX for the reviewers.

One could definitely imagine a UX/DX that would. (I do apprecaite github's UI generlaly).