I've also observed some similar issues regarding frametimes, those seem stable for most of the time, but randomly occuring hitches and spikes are often happening, they last like fraction of second but are obviously visible. I did update of BIOS, drivers etc. but i think it is most likely some driver issue that needs fixing. What's interesting, is the fact that rx 570 which is an older gpu seems to be more stable in this term overall, at least on older drivers ( 21.12.1). Issue is mostly visible in DX11 games like BF3, BFV, ets2 etc.
My PC
I5 10400f
Asus prime b460 plus
16gb ram ddr4 cl 15 working at 2666mhz (corsair vengeance LPX)
XFX RX 6700 XT Qick 319 Black
650w bronze psu
Pcie x1 wifi card
Driver version: adrenalin 22.5.2 ( but the same goes for 22.5.1 which i also checked)