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?

There's essentially no multicast over the public internet

That was the idea once upon a time[1], but it's been dead for ages.

1. https://en.wikipedia.org/wiki/Mbone

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.

funny enough.. my team probably killed off (one of anyway) the last tier 1 internet multicast deployments over the past few years.

Multicast has dataplane resource scaling issues and, frankly, CDN has become the solution to what multicast solves.

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.