Another tech support question. PC randomly shuts down every once in a while, just replaced GTX 1070 with an RTX 3060 ti.

Howdy, figured I'd add to the tech support posts of late to see if anyone has a clue as I've googled a fair amount and haven't found answers (although I don't have much to go off).

TL:DR Computer randomly turns off, this has happened 3 times in the past month and a half, all 3 times I'm playing FFXIV and watching a video on youtube on the side, although this largely could be a coincidence as I play a decent bit of FFXIV and I pretty much do this (watch YT/Netflix) every time I play FFXIV. Can't figure out whats causing it. I'm more so worried something will get damaged in the long run unless I figure out what's causing it.

Last christmas I decided to upgrade my rig, I've got an MSI MAG B550 Tomahawk with a Ryzen 7 3700X with a Noctua NH-D15 and 32GB of RAM, Corsair RM750x and I kept my old GTX 1070. All was good since upgrading.

About a month and a half back now I was able to get an RTX 3060 TI, for the first two weeks I had little to no issues, then one day while gaming my PC just reset. no BSOD no error just flat out restarted. I was playing FFXIV watching Netflix on the side and after this i was paranoid to no end about watching something while playing, I ran a few stress tested including letting XIV + Video play while working for a good 5/6 hours and nothing happened. 2 weeks past with little to no issue again and I'd started to forget about it, then it happened again.

So I started un-installing and re-installing all my drivers, updating my BIOS etc. I've basically done everything bar formatting, once again it had been fine for a few weeks until a few moments ago.

I'm stumped at this point, I'm likely going to format and potentially try and re-seat the card to see if that'll fix anything as this has only happend after I upgraded my GCard but considering it's so intermittent as to not happen for a good couple of weeks then randomly boot me off I'm not going to know for another Month.

Anyone go through anything similar or have any ideas? I appreciate this is literally one of the broadest "the f*** is happening" questions you get for PCs, My best guess is PSU, I'd like to think formatting isn't the issue as it's just hard resetting without giving be a BSOD first (if i got BSOD'd i'd assume software) but by all accounts my PSU should more then enough for my setup. I've not got any other issues, I'm running two seperate power cables from my PSU to my GCard (not using 1 cable split). I didn't have many issues installing it so I don't think i damaged the port, it doesn't seem to be temp related crashes as nothing ever gets much past 65 as I'm not stressing the card that hard.