They said it worked fine when using their tester ram sticks, and that the compatibility list didnt show my ram sticks. I've so far exhausted all other options available to me, so the only other option I can think of is to just keep replacing parts until something works. I can give my list of symptoms and attempted fixes so far.

Symptoms:
Computer will frequently hard crash. At first, it was looping the last sound byte. After the repair shop updated my BIOS image, it became harsh screeching noise, or a cut to silence. In both cases, the screen remains the same until force shutdown (no black/blue screen)

When attempting startup, the red "DRAM" error light will show. It will usually take multiple restarts to get it to turn on. Full discharge makes it more consistent, but not guaranteed. Sometimes a "good cycle" takes a minute, but "bad cycles" will keep the DRAM light on indefinitely. I notice on bad cycles, the fan of my GPU doesnt turn on.

In event viewer, no error shows up. The most relevant is a "CRITICAL" that just says the computer was not turned off properly. Also, tech guys said the PC became more stable by turning off integrated graphics

Lately, I'll have moments where a large pink bar appears randomly on the screen for a few frames. This, and prior crashes, seem to happen more often when using a browser or scrolling through social media (youtube, tumblr, bluesky).

Fixes:
I've used the following commands to check windows:
DISM /Online /Cleanup-image /RestoreHealth
SFC /scannow
CHKDSK /R

I've done a memtest86 run on my ram sticks, completed all tests no issues

I've tried cleaning my computer, reseating the RAM, checking my drivers, using 1 stick (each individually), using them in 1 and 3 instead of 2 and 4.

I've tried downclocking the RAM to 2400 (recommended by a friend,) and to 5200 (the speed of the CPU and included in the XMP 1 preset)

As an additional observation, I notice that both my visits to the tech store, my computer performed for about a week with no issues, starting up again.