Found our bottleneck after months of searching. HYTOPIA servers are about to be able to run 200+ concurrent players in games @ 60 tick without issue. We can run 500+ concurrent if we wanted with a little more tuning. All lag / jitter / stutter should be gone as well too.

This is on a single 2.5ghz core. We up the clock speed or add parallelism across a number of things and that number goes up significantly.