Check the Startups tab in Task Manager and disable all but the known trusted ones 1 at a time, checking performance each time.
Also, Windows Defender is not at all a catch all. I recommend scanning with Malwarebytes.
You may want to go through and check all your hardware and cable plug connections to see that they're locked in tight too, and even try swapping out the video cable if you have a spare.
Also, make sure you have any redist required installed for the problem games (DirectX, Visual Studio, etc)
Lastly, look in Event Viewer to see if there is any other info besides CRITICAL PROCESS DIED. Worst case scenario, you could have a faulty MB, but before trying to replace it, I would check to see if there are any BIOS updates for it that could be needed.
There's been 14 BIOS updates for that MB. If your Samsung SSD is an M.2 type, it's imperative you be on at least BIOS version F41. BTW, there are drivers for Samsung M.2 drives as well, make sure it's installed if you have an M.2 vs SATA type. You don't have to use the Magician tool though.
https://www.gigabyte.com/Motherboard/GA-A320M-S2H-rev-1x/support#support-dl-bios