I wouldn’t necessarily trust that xmp was set by the dealer. Check it out and be sure. My daughter bought a pre-built from MicroCenter last year and guess what! Yeah, xmp off.
In my case, disabling hyperthreading eliminated major stutters and most CTDs and stabilized FPS. Ymmv.
I have a i9 10900, water cooled, a 3090, G2 headset, 2 32" monitors at 4k., yoke, throttle, pedals, more fans to move air thru the case than I’ve ever had on a rig before, and 2 buttkickers running thru an add-in sound card. I upgraded from a mid-grade 850 W ps to a higher-quality 1000 W ps and that put an end to all remaining CTDs (that aren’t the result of discernable add-on conflicts) and occasional BSOD crashes. Again, ymmv, but these are things that have worked for me and may work for others. Try 'em, don’t try 'em, whatever.