The manual bare repo setup obviously offers no user access management beyond what the system's SSH configuration provides. Beyond that, a bare repository is actually an essential Git feature and what software like Gitea and even GitHub uses behind the scenes.

Given all users can share a user account on a server, it will behave exactly like you expect it to. Again, that's a core Git feature. Additionally, AFAIK Git has its own locking management. Also look up the `--shared` flag. `man git-init` is very helpful.