- SourceHut: https://sr.ht/~sircmpwn/sourcehut/
- Forgejo (used by Codeberg, etc.): https://forgejo.org/
- https://about.gitea.com/ (F/OSS MIT license self hosting GitHub like instance)
Forgejo, on the other hand, is a drop-in replacement for GitHub.
At a customer we're implementing GitHub Actions and even on our Dev environment there are so many hickups with GitHub.
Might be pricy though.