Oxenai is private but their vcs is open source including the server, so you could self host it for free and use it with other people. The vcs itself is a little bit like git but with native large fial support

I could be wrong but I think besides being able to self host for free you can also pay for something where they help you set it up and stuff

Something nifty also that you can do is that instead of them training on your data they enable you to train your own models on it and download the weights.

Definitely agreed its hard to trust anything you cant audit 100%. I think a non profit structured the right way would probably be pretty trustworthy not to do anything egregious like training on your data though. Or some way maybe to make the thing transparent so you know what happens with the data and you can basically audit the company somehow. I dont know if you would need to go as far as encrypted repos, that seems a little too paranoid but that would be a really interesting idea for a company although the target audience is probably limited