Regarding the first question, for me PeerTube has a similar problem as with other fediverse stuff, which besides a lack of greater adoption is a scarcity of sites with a positive, distinct identity/community (last I checked at least) to encourage more people to use it.
Off the top of my head in terms of PeerTube, only TILvids.com comes to mind, which is cool, but remains primarily tech and specifically Linux-related educational videos. I don’t mind that, but it’d be cool to see a broader range of educational content on there.
Appreciate this post OP, as I’ve wondered similar at times when not wanting to fuss with another machine for self-hosting (as often it’s not the case that I could run the server software on my main system).