Hi and welcome to the forum.
What you described could be caused by a lot of things (btw thank you for putting your whole system specs).
Besides changing your PSU, what else have you tried?
- Have you tested the temps to see if the CPU and GPU stays cold, or if they get too hot and then the PC shutdown? (You can monitor temps with many apps, I used hwmonitor and/or hwinfo64 - no need to install any of those, you can download the "zip" portable file from the oficial website)
- Have you tried to take out everything and just leave the motherboard, the CPU, 1 memory stick and the storage to see what happend?
- Have you tried bulding up your PC over a wood table and see if it still turns off and restart?
- Have you tried going into the BIOS and let the PC stay there for 20 mins and check the "monitor" tab too see if the CPU (which should be at idle doing nothing) stays at a normal temp (depending on your cooling solution and room temp, it should be between 30~40°C).
- When was the last time you did a full clean install of Windows?
If I were in your place, I would start by tring the PC with the bare minimum parts (CPU, motherboard, 1 RAM stick and only the boot drive) over a wood table or a cardboard piece and see if it does the same thing. If by doing this, you see no issues, I would then add (either) more RAM, or the GPU and see what happend. Then I would add the case fans, then the other drive, and soo on.
There are lots of things to try out, it would take a lot, so if you don't mind share some more info, and see if anything of the above share some light to your problem.
Cheers!