Every team should follow a plan, fine on a side project, but if you work in a large codebase with a bunch of devs, you need to have some sort of workflow to avoid stepping on each other's toes.

bug fixes are supposed to be small, contained, if they're rearchitecting the codebase, then they're not _bugs_, but tech improvements, and need to be addressed differently and I agree that this should be flagged in the PR.

a PR review is the final defence line before a QA