Here is how I think of it. When I am actively developing a feature I commit a lot. I like the granularity at that stage and typically it is for an audience of 1 (me). I push these commits up in my feature branch as a sort of backup. At this stage it is really just whatever works for your process.

When I am ready to make my PR I delete my remote feature branch and then squash the commits. I can use all my granular commit comments to write a nice verbose comment for that squashed commit. Rarely I will have more than one commit if a user story was bigger than it should be. Usually this happens when more necessary work is discovered. At this stage each larger squashed commit is a fully complete change.

The audience for these commits is everyone who comes after me to look at this code. They aren’t interested in seeing it took me 10 commits to fix a test that only fails in a GitHub action runner. They want the final change with a descriptive commit description. Also if they need to port this change to an earlier release as a hotfix they know there is a single commit to cherry pick to bring in that change. They don’t need to go through that dev commit history to track it all down.