> RAM: 64 GB DDR4 overclocked to 3733 MHz, stress testing 24 hours stable

OP, it may be worth downclocking the RAM to 3600MHz (while tightening timings) unless you have a golden chip with >1800MHz Infinity Fabric. Decoupling IF and memory speed can cause huge latency (90ns on my 3950x).

Obviously you want a baseline and benchmark from there, but you clearly know what you are doing.