In some countries you can get fined for torrents.

So he would need VPN and/or debrid

Simpler and cheaper to go direct link download as OP.

Yes, there should be instance caps, and they should be visible to users.

That way users can scale, choose, without much thinking.

This same techinque works everywhere, for example MMO games. You have availability visible and choose servers according to it.

This would fix scaling partially without much technical changes.