They all claim to be anonymous. And yeah, nobody can independently validate the no logs policy, even Mullvad that has been security audited doesn’t let anyone near their production environment, so what they release to the testers might not be identical to what they use live.

Calling TOR anonymous is a big stretch through, a bunch of commits to the code have been traced back to the CIA if I remember correctly, and various intelligence agencies worldwide are running exit nodes and log everything they can get their hands on. Whether they can decrypt it with current tech is another story, but you better believe they don’t just delete it.

Likewise, never trust that tor is completely anonymous. There are a limited number of tor nodes, and an extremely limited number of exit nodes. The barrier to entry to stand up thousands of nodes is simply a cash problem. It certainly beyond the reach of most corporations, But I wouldn’t want to do anything on tor that would draw the ire of a large government agency.