I've heard of all of those - mostly through my friends.
However, as to your larger point - you're right, most people don't know about these.
I would argue that those who want to escape Google's grasp should be willing to encourage person-to-person sharing as an alternative to the recommendation algorithm. Sure, 99.99% of the population isn't browsing PeerTube, but I bet you that most of them would be willing to watch a video hosted there if it was suggested to them by their friends.
This might be a good idea in general. Think of how much better ecosystems we would have if people relied on their friends to make personalized recommendations to content on any platform, as opposed to engagement-optimizing automated algorithms that exclusively recommend content on a single platform.