Or Forgejo, which is a fork of Gitea and is what Codeberg uses. They explain their advantages over Gitea here: https://forgejo.org/compare-to-gitea/

The tl;dr is that Forgejo is maintained by a non-profit whereas Gitea is maintained by a for-profit company, and Forgejo is completely open-source whereas Gitea is open-core with some features only available in their hosted service. Forgejo also has better testing and a bigger focus on security.