Not sure if this is related but have you checked whether you are being throttled in anyway?
I happened to have intel XTU open when i was in a multiplayer session and experiencing stutters and i noticed the current/EDP limit throttling was maxing out and also my cpu temp was up to 86 deg. Digging a bit deeper i installed HWinfo which told me i was being throttled 45% of the time.
I ended up under-volting my cpu and dropping the boost clock from x46 to x45 - stutters were pretty much eradicated.
I was also running open xr tools, mainly for the turbo mode, which had boosted my performance in the past. Now, I discovered, it was holding me back. I reset to defaults and disabled it, this allowed me to push Virtual desktop from high to ultra at a solid 72hz.
I get the odd stutter every now and again but i believe this is a network issue as i'm connected to US servers from AU.
I'm running an i5-11600k, 48gb ram, RTX 4070TI