GitLab has leaned completely into becoming an enterprise DevSecOps platform at the expense of open source. Their 2015 homepage [0] emphasized its own open source nature and their free offerings. Their current homepage [1] doesn't mention open source at all and only includes the word "free" in the phrase "free trial". The banner at the top of the page currently reads "GitLab 17 & the future of AI-driven development". They've come a long way from being the underdog champion of open source.
Gitea is doing better for now, but the trademark was transferred to a for-profit (Gitea Ltd) and the main gitea.com domain is now being administered by a different for-profit (CommitGo, Inc), with very little transparency about what either of those for-profits are doing and how they'll use their ownership of these key resources. In light of recent license changes by major for-profit open-source companies and the recent behavior of GitLab, I'm not thrilled about Gitea's IP transfer to multiple opaque for-profit companies.
Codeberg.org's fork of Gitea (Forgejo) has a governance structure that is more appealing in that it is not profit-oriented, but I'm nervous about overmoderation in the Forgejo community [2]. Constructive opposition to the election of moderators (based on their past abuse of authority) got edited away as "ad hominem attacks" and has since been completely deleted from the election thread. They're a nonprofit, but after watching the episode linked below unfold and then get swept away entirely I don't trust their governance process at all.
There are other, smaller options that have fewer problems, but none with anything like the features that GitHub offers.
[0] http://web.archive.org/web/20150316170559/https://about.gitl...
[2] See this HN discussion: https://news.ycombinator.com/item?id=39397269. The critical comments that had been edited at the time of that HN thread have now been eliminated entirely from the linked issue and the only Internet Archive hit that's left for that page is from after the comments were completely deleted. That's not a good look.