If you're interested in E2EE git repos, you might be interested in a project I've been maintaining for a few years now: git-remote-restic. It stores the git repository in a restic repository hosted on any untrusted storage. It is designed for secure archival, but it does support multi-user access (no web UI because, of course, it's E2EE).
> no web UI because, of course, it's E2EE
I've used E2EE messenger apps over a web ui before, are you sure that's not just a design choice?
It’d be technically possible to do it, sure. I meant that in comparison to the linked project, where you can view the file paths of the git repo (but not the file contents) on any off-the-shelf git forge. With mine, its not possible to use an existing web UI.