This may be silly question, but since tor is single threaded, that means having huge server is technically useless, what about splitting the server using Proxmox or other software, this could possibly spread the load across all cores/threads? Hm?
There is no way to split a relay's tor process across CPU cores. The Tor Network does allow you to run up to two relays with the same IPv4 address though, so many people choose to run two relays on one server. Some relay operators with a large number of IP addresses run up to 16 relays on the same server.