What's better context than presenting all the related atomic commits at one time in a single pull request so you know exactly which related set of commits are being added and for what reason? Slap a merge commit on and you can revert the whole thing! But your commits are a mess, and I want to see clean ones. That is what interactive rebase is for and what attentive project contributors would do in order to clean up before or during the merge process. Why is it fair to ask someone to change syntax formatting to but not cleanup their commits? Because the latter is a "big ask" for someone who doesn't know their tool.
Then we get back to the problem of not having independent review, CI status, and deployability for each individual changeset. There's no amount of git competency that changes the fact that GitHub PRs operate at the branch level, not the commit level. I've actually done exactly what you say many times -- interactive rebase to clean up the commit history -- but the end result of that process is the creation of multiple "stacked" branches, solely so I can submit multiple PRs and conform with the team's expectations.
> There's no amount of git competency that changes the fact that GitHub PRs operate at the branch level, not the commit level.
Most all CI tools support per-commit checks with simple configuration/scripting of their execution DSL/API. In GitHub, push actions already works this way. You can do the same thing on any branch after a PR is opened: on synchronize you can iterate over all the updated refs, run checks, and publish results to the commit status API https://docs.github.com/en/rest/commits/statuses, and https://docs.github.com/en/pull-requests/collaborating-with-....
