Power cycles under load

[Fenceless]

Under (certain) loads, my computer will completely cycle power. I'll be playing AC:Odyssey or the likes (high graphics draw, i'd assume?) it'll turn all the way off, lights go out, fans spin down, 3-4 sec later it turns back on without me touching anything. Both the PSU and the card are less than 2 months old, both work perfectly fine 99% of the time.

Specs:

ASRock Z270 EXTREME4 (I have not updated the bios from what shipped with the board, as I have never had issues)
i7-6700k
16gb Dell OEM ram (Given to me by a friend who upgraded his ram, works fine and shows no issues with the normal ram tests)
RTX 2060, EVGA SC Ultra Gaming
Corsair CX750M
Corsair H115i Pro Cooler

CPU temps max out between 40 and 60 depending on what i'm doing (as of the last time I looked at temps so a few hours ago), GPU temps max out at 60.3.

HWInfo says 5v is running at 5.04v and 12v is running at 12.192, and GPU power (while just sitting at idle) is around 16.2v avg. My multimeter is currently in use at work but I will try to take voltages when I get a free day on saturday.

I have triple checked every cable connection (the 4+4 on mobo, the 6+2 on the 2060, both connections to the PSU rails,) none of them are pulled taught, all connections are nice and snug. I don't know a ton about computers, just enough to build one and make sure it's working well. My amateur knowledge would assume it's a PSU issue.

Hope I provided enough info, just sorta tried to put down everything I could think I'd need.