Goldilock

Sounds like PC is shutting down, might be PSU issue.

Best case scenario: Broken display cable Worst case scenario: Dying GPU Both cases shows similar symptoms (black display but everything else is functional).

I had exact same issue as your. That card is probably dead even though it spins and lights up no issue. My card (also RX 5700) now still sitting in my drawer.

That right there might your main culprit. If I were you, I would roll back to Windows 10.

You should consider fresh windows on brand new HDD/SSD because the only culprit left is your SSD. 1. It should not be windows issue because you did fresh install 2. It's not heat issue because you ran stress testing just fine 3. It's normally not PSU issue because it doesn't shutdown BIOS normally do not get corrupted under normal usage. BUT there is a chance the stock OC setting causes the crash.

You need to start saving, sooner or later once it refuses to display, you'll need new GPU.

My RX5700 was exhibiting the same as issue yours. Sadly I had to replace the GPU because after a while it refuses to output display whatsoever.

My RX 5700XT blew, not really sure why. Either it's air starved or power starved. I had 550 watt C rating PSU and "gaming" PC case. It seems like last 2 gen of GPU, anything above RTX xx60 dan RX xx60 really need decent supporting component. I personally wouldn't touch used 6700xt without B rating PSU and brand new case.

I feel you man. GPU prices are still high even after crypto crash. I had $100, I can only afford GTX 1660 (used). For $100 + a little bit there might also RX 5600 (used).

Most likely one of the capacitor died considering the age. If you can find local electronic repair shop, they probably can just replace the caps and resistors with exact same value and you'll be good to go for another decade. IMO you would be hard pressed to find better system at $500 mark. Cheapest AV Receiver is already $300, not including Subwoofer, center speaker, front speaker, and rear speaker which could easily another $200 EACH ($800 total). Edit: I'm not surround guy, but me personally Center Speaker + Front Speaker is more than enough for movies. My Wharfedale put out more bass than I already needed, so I also don't run any subwoofer.

I personally would go with NZXT C1200, this is stil A Tier. And you cannot go wrong with ATX 3.0 https://cultists.network/140/psu-tier-list/

That's the thing with dead CPU. First they would crash under load, then crash at idle, and next you know it no display whatsoever. If you can find repair shop or friend with spare CPU that would be great start to check. Yes, PSU blows up sometimes. But EVGA GT is still B tier PSU.

I know it sounds crazy. Have you considered RMA your CPU? Believe it or not, it sounds like half-dead CPU to me.

I had almost same issue, then I RMA my CPU (Ryzen 5-3500X). My local distributor concluded it was dead CPU. It worked fine for 2 years, barely play any games, run very cool 70c at gaming since I always use vsync. But it's dead anyway, might be worth checking spare CPU or service center that has spare CPU to try.

IIRC Thermaltake GF3 comes with white variant.