For some repositories that probably will be terminated on Github at some point, I have set up cloning on private Gitea instance. Disabled tree overwrite on some branches and have them backed up in case something else happens. So far I have never needed to use it, but it makes me feel better.

And no, Gitlab is not as easy to maintain. You can probably set it up in Docker easily, but overall it has many moving parts and it requires more resource, while Gitea is just a single Golang binary and is a joy to use.