If you’re looking for a bare bones solution, and you already have a machine that you can SSH into, you could just use that. There are desktop GUI/TUI apps galore that you can use to inspect commits, branches and such.

At work I’m in the process of planning a move from Subversion to Git. So I’ve been looking at Forgejo, a hard fork of Gitea maintained by Codeberg. It has all the important features of other forges like GitLab and Gitea. But is completely open source.