Pc sudden restart but my fans led is still on and running

I need help everytime I play or idle my pc suddenly restart but my fans and it's led are still working it just sudden restart while im gaming or idling I tried everything I also undervolt my cpu thinking that is the cause but its not I just recently upgraded my power supply thinking that would fix the issue but that didn’t. I have had my ryzen master app open on my 2nd monitor while playing and don't notice any overheating.

It will do it randomly I can have it happen once and as soon as I relaunch whatever game I'm playing it won't do it again for the rest of the day or it will just keep randomly rebooting every few games. Sometimes it will reboot and I will just open discord and it will reboot again. I once reapplied my thermal paste and it seemed to have fixed it temporary. I have ran memtest on both ramsticks and they both passed. I am just out of ideas what else I can do.