I always thought that online media services used multicast protocols, that is, after the initial point to point connection all data packets should be transmitted once, then replicated at router level for every subscribed user. If that's the case, 30 users seems a pretty low number since it would translate into maximum 30 concurrent connections while the generated traffic from the server point of view would be just slightly higher than a single stream for a single user. Or maybe carriers bill multicast traffic differently?
Some ISP-run and or company/network-internal ones do, but over the public internet there is no infrastructure for that, so the vast majority doesn't do it.
Yeah that's roughly correct. I actually hadn't found hetzner when I was doing my initial research but it definitely looks like I should be moving over.