B450 Steel Legend Corrupted files on copy

A few updates:

1) I've replaced RAM to the one in QVL - Crucual Ballistix BLS16G4D32AESB x 2
2) I bought a new gold certified PSU
3) I've passed memtest86 with no errors (with the old and the new RAM sets / only one stick at a time)

I've tried to work with just one stick of RAM in different slots - done.
The Support recommends me to remove SATA devices and change M2 slot - done.
Same corrupted data between RAM and storage.

Also, got a few BSODs 0xc000027a on Windows install and just immediately after I had been thrown into UEFI with no detected RAM at all :)

Might it be the MoBo or the CPU? I've looked into the CPU pins and found no damage.

If this is happening even with XMP off then make sure you have your RAM installed
in slots A2 and B2 and that they are properly seated.

If any of your drives use a SATA cable you may also want to try another cable. I
am guessing that both your drives are M.2 however in which case make sure they
are both properly inserted into their slots and not overheating etc.