Sometimes it's okay to take liberties with good practices - especially when learning, or when the world is on fire and a push needs to happen now.
The unwanted reality we live in.
When you commit in git, that saves the whole project as a "snapshot". If you find yourself lost in some rebase hell or whatever, just reset HEAD back to a previous commit. It's simple as that! (git reset --hard <commit>)
Why I decided to reply to your comment was because this is a very crucial part of learning git. When you realize that you can always go back to what was before, you can start experimenting more freely.
Unless part of your surgery involves files that do not yet live in the history, or you're working on a detached HEAD in a mid-merge state, or... git reset --hard is a very dangerous operation unless you're 100% sure of the entire state of the repository. That is a very rapid way to lose work if you're not perfectly diligent.
And sure, you shouldn't have to back up .git or your workspace, but sometimes, it's a hell of a lot easier to ripcord out and say "screw it" if you have a complete workspace from before you decided to launch down the rebase hole or whatever.
If it is committed, it is safe. You can go back to it. If you messed up your branch, just reset it to something that was good. No need to do manual backups.