Phabricator is pretty good except it has pretty much zero CI integration. Kind of annoying.

You also have to pay to even comment on issues. I think that's a pretty great way of getting companies to pay for support but it's also annoying if you want to work with other freeloaders on issues.

Also it's written in PHP which means you aren't ever going to want to read or modify the code. No different to GitHub, or probably even GitLab but I can definitely imagine modifying Gogs/Gitea.