Generally, you "stack" your commits/PRs and review them in small units (which I think is what you mean by working on something else without making any Git check

Generally, you "stack" your commits/PRs and review them in small units (which I think is what you mean by working on something else without making any Git checkouts). But you can certainly create new "branches" of development which aren't stacked on top of each other. They just don't have to have names. You can consider them to be "anonymous" branches. The main advantage of 1 commit per PR is to review and commit smaller changes (a single commit at a time).