X99E-itx/AC crash, 3 beeps & compatible memory

Hello!

I have a computer using the X99E-itx/AC motherboard with i7-5820K, Windows 10, GTX 970. It has been running for about 10 years and just recently had a crash it has so far not recovered from. I wasn't using the computer when it happened so didn't see any problems until computer was on, fans running but no video display.

When I try to reboot, lights come on, fans run, I get 3 beeps from the motherboard, but no video output. I read online that 3 beeps for ASRock indicates a memory issue. I tried removing the 2 RAM sticks and replacing them with new (Crucial Pro CP2K16G4DFRA32A, 2x16GB) but no change in behavior.

I tried pulling my GPU and putting in another older GPU but still no luck, still giving the 3 beeps.

I'm considering trying a different RAM module(s) since I know this motherboard had some RAM compatibility limitations. Is that a likely issue or might the 3 beeps not actually indicate a problem with the RAM itself?

I looked at the memory compatibility list here: https://www.asrock.com/mb/intel/x99e-itxac/#Memory I don't see any of these exact model numbers available locally. Does it need to be an exact match or should the off-the-shelf RAM at Best Buy work?

The RAM available locally (Best Buy) is:
Corsair Vengeance LPX CMK32GX4M2E3200C16
Corsair Vengeance RGB Pro CMH32GX4M2D3600C18W
Corsair Vengeance RGB Pro CMW32GX4M2D3600C18
Crucial Pro CP2K16G4DFRA32A
Corsair Vengeance LPX CMK32GX4M2D3600C18

Other than trying different RAM, I'm kind of stumped and thinking something on the motherboard may have failed.

What else should I try or look for?

I don't have a lot of data at stake, have system backed up but I'd like to get the computer going again if it's possible.