The point isn't that GitLab has more, the point is that running these things at global scale is pretty complicated, and everyone has problems. "Just switch to GitLab" is pithy but isn't in itself an actual solution.
Perhaps this is a continuing argument for self-hosting, especially if you don't have to expose the instance publicly. But then, if that's an option, you can also self-host GitHub (though I have heard less anecdotes about the stability of that).
I'm confused. You can do zero-downtime backups and replication of databases. I don't know what your company / Gitlab are doing but it seems wrong.