I'm a strong believer that PRs should be merged via a "squash and merge" strategy, with the singular commit being descriptive of the overall change and having a link back to the PR for deeper story analysis as needed. I'm also a staunch believer at this point that PRs should really focus on one thing as well. If when working on a bug you discover another semi-related bug? Open two PRs.
Let main be the story of how code got from point A to B, and PRs be the story of how each incremental step was made.
PRs only live on GitHub, what happens if it gets shut down or it accidentally loses some data?
the entire repo lives only on github as well, there is no meaningful difference between git commits and PR comments in a github-hosted repo
Uhm you might want to look up git clone