I remember when it came out in 2011 or so, people were agahst and in awe of how fast it was.. like this was impossible.  And some smart developers went digging to try to find the "problem" because it must be doing something wrong to get that speed.  And what they discovered was that it was simply using several really smart techniques in ways people hadn't put together before, like copy-on-write, b+ trees, mmap returning direct pointers to the data instead of copying it, etc.

I also think it is probably at or very near the maximum theoretical performance.

Of course unlike you, I don't utilize that performance on my relay.  wss://chorus.mikedilger.com:444/ is currently only serving 15 connections.