Wait.
Does Portainer ask your email? I haven’t used it in years. I though it was just a container that you run, with mounted docker socket, and that’s it.
Is it now doing some “telemetry” and sending user data, like email, to their servers? If so, I’m glad I’m not using that anymore.
git is already a decentralized version control software. Your local git repos are mirrors by themselves.
Put some
git fetch
in a server crontab, and you’re done. You can access them via ssh if your user have permissions.