> If we take say, Vultr as an example for outgoing data costs, that's something like $100,000 of data for a single video.

I'm not really sure what you didn't understand about distributing the video and cost.

Can you explain it a little? Because I'm not sure I get it. As far as I know peertube is centralized with a P2P element on top, but P2P only works if at least one side has an open port.

It sounds like you get it but what I'm saying is you just add colo'd (or whatever) peers. Nobody in particular needs to be responsible for that. Bandwidth in Eastern Europe, for example, is dirt cheap - practically free. It'd be similar to how we do Mastodon: a bunch of different peer networks with a bunch of different funding and management models. You don't need to rely on the instance server for hosting, just initial seeding. Think of it like the original seeder in BitTorrent (a model which we see working great to this day because people rent dirt cheap seedboxes.)

Does peertube support using another host as a dedicated P2P peer, and it would load balance over available hosts? I feel like I looked into that before and it was only clients watching the video that could do it.

But if it can now, that would be the missing piece that I wasn't getting.

As far as I understand it that is possible in multiple ways. What's not currently possible (unless something changed) is load balancing write operation.