As for bandwidth and server costs, with gigabit fiber and faster getting more and more common, a lot of "just starting" streamers could comfortably support 100 viewers at 10 Mbps quality straight off their home Internet. Fewer viewers? Stream in full 4K 120Hz at 50 Mbps do your friends if you want.

PeerTube has the advantage of WebTorrent, so an average channel doesn't have to cost too much in hosting fees. Plus it's all legal content you own so those are fully legal torrents. It's also good for ISPs because they might have to transport that video just a few blocks across instead of all the way to the closest Google/AWS/Cloudflare datacenter and back.

I get 500 Mbps unmetered on this $40/mo server, I think it could comfortably handle a couple thousand subscribers before I'd have to scale up, possibly a lot more with a healthy pool of WebTorrent viewers.