in cs go cpu usage is like 60% gpu even lower it limits fps around 60 on max setting.same thing in other games exept cpu is 100% in apex.reinstalled drivers, scaned pc for malware, benchmarked gpu and cpu, temps are low , everything seems fine only possible reason i think of is that i have 1x8 gigs 2400 mhz ddr4 single channel ram which i allready checked with windows memory diagnostic tool .
It sounds like your FPS is capped at 60 so the system is only going to be pushed to make those FPS which doesn't take much which is probably why your seeing such a low usage. Make sure Vsync or any FPS capping is off.