I constantly rebase my feature branches regardless of how many commits there are and whether I’ve pushed any of them. So long as no one else has checked out my branch it’s perfectly safe. Personally I find rebase merge conflicts far easier to work with. Traditional merge conflicts are “Here’s someone else’s changes, figure out how to merge them into your feature branch.” Rebase merge conflicts are “The main branch has changed since you made your changes. Re-apply your changes to the new base.” For me/my brain, the latter is so much easier. The only time I ever run into problems is when there are merges in the history I’m rebasing. Which I avoid by never merging into my feature branches, only rebasing.
And if it goes wrong, just git rebase —abort. Or if you already completed the rebase, git reset —hard origin/YOUR-BRANCH. Or if you majorly fucked up, use git reflog to find a good commit and reset to that. Zero risk if you know what you’re doing.