Selfhosting gitea is trivial, I'm saying this as someone who has been doing it at work for almost 6 years. Our experience has recently prompted another org (run by people we know) to move off GitHub, they also seem to be happy.

There are plenty of alternatives to Github, from Gitlab and Gittea to Forgejo, but Codeberg is not one of them, which is what I wanted to stress.

Tangled.org