As others have said, a traditional off site backup will work. How do you plan to perform a restore, though? If you need the self hosted source repo, it won't be available until the infrastructure is stood to creating another circular dependency.
I'm still in the early stages of exploring this, too. My solution is to run a local filesystem git clone of the "main" repo and execute it with a Taskfile that builds a docker image from which it can execute the ansible infrastructure build. It is somewhat manual but I have performed a full rebuild a few times after some Big Mistakes.