XMP not working anymore (BSOD when enabled)

I bought some new and used parts and built my current PC build with my brother in November 2023. Here's some context and information before I get into the problem:

i9 13900k
4090 Aero OC
ASUS Prime Z790-a Wifi
CORSAIR Dominator Titanium RGB DDR5 RAM 2x32@6600MHz CL32

After building the PC, it ran every game smoothly, and everything was fine. I even had XMP enabled, and I noticed the difference. I had no problems whatsoever for about a year and a half. It started with my PC being unable to run certain games, and I posted on the game's Discord forum, thinking I would be able to get support to fix the issue.

I would get a lot of Unreal Engine error codes. At some point, I stopped playing the games I loved because of it. Then, after a while, I started getting blue screens out of nowhere. I went from crashing errors to BSOD, and I would copy the BSOD error code and look it up. It was random, but mostly I got 'kernel' codes. I took my PC for a diagnostic test at my local MicroCenter, and they said it was the RAM sticks, so I had an RMA and replaced them.

Everything worked fine for a week, and again it started doing the same thing, so I ended up buying a cheaper pair of RAM, thinking it would solve the problem. And it did, for a while. My PC worked with XMP enabled on the third pair of RAM sticks (Corsair Vengeance DDR5 64gb, I forget what speed). Eventually, I turned off the XMP, and my PC would work, but I would notice the difference in performance, and I just played with it. And eventually, it would BSOD even with XMP disabled. At this point, I was in college and couldn't worry too much about fixing my PC, so I just let it sit there for a while.

I did various things rule out different things, like updating my Bios firmware, reseating the RAM sticks, updating my drivers, and hard resetting my PC, but nothing worked; it would freeze on the blue screen after my BIOS said "Attempting to repair" (or something along those lines).

Anyways.. I let it just sit for a while and saved up some money. I didn't want to go through the struggle of switching out each individual piece, because at the time, the 13th and 14th generation of Intel CPUs were getting bad reviews, so I thought it could be the CPU. I ended up buying a new CPU, heatsink, motherboard, and case. I kept the RAM sticks the same because I had two that I could switch between in case one didn't work, and I planned on rebuilding my PC. Since my PC could not boot into Windows, I couldn't wipe my SSDs for the swap. So I dropped off my SSDs at a technician's house, and he said he would wipe them for me. He told me my SSDs were corrupt and that was the main reason for my failures. When I reinstalled them, everything was completely fine, it runs perfectly fine, and I have been running my PC and different games pretty smoothly, even the games that I had issues with originally. But now whenever I enable XMP, it does the same thing, so I'm afraid to enable it again and cause the same issues.

Is this a common issue with any of my hardware?

Has anyone had this and found a fix for this issue?

Is this a RAM problem? Or is it deeper than just the RAM?

Should I get my PC re-diagnosed?

If you have any questions, I can answer ASAP. (Also I'm not sure if r/buildapc is the best for this topic, but I'd assume to start here. If theres a better alternative, please let me know too!

And thank you to anyone who helps, in advance. Sometimes I get ahead of myself and want to rush things and forget to thank those who help.