Aurora R12, RTX 3080, black screen under load

Aurora R12 Specs:

• CPU: i7-11700f (liquid cooled)
• GPU: AW RTX 3080
• RAM: HyperX DDR4 3200MHz 2x8GB
• PSU: 1000W

Been working through this issue for probably the better part of 2 months. I've tried a whole long list of things:

1. Fresh OS install
2. DDU and reinstall from Nvidia, Dell, Device Manager
3. msconfig startup only Windows apps
4. Uninstall iCue, AWCC
5. TDR Delay changes
6. Disabling hardware acceleration
7. Setting power to high performance
8. Disabling Gsync
9. Disabling OC
10. Trying XMP1, XMP2, and Disabling it
11. Disabling/enabling Intel Speedstep, Speedshift
12. MSI Afterburner undervolting, unchecking IO boxes
13. New PSU (Tried corsair 1000w from Best Buy)
14. New Motherboard (Dell RMA)
15. New GPU (Dell RMA)

The mobo and GPU swaps were both from dell support. The new GPU was the "last resort" and it actually resolved the issue, but only for 3-4 days. Now I'm unable to run any game on the tower, and cannot complete any UNIGINE benchmarks either. So....what exactly happens?

1. Game with high load kicks off
2. GPU fans ramp up
3. Screen starts flickering
4. PC Freezes
5. Screen goes black
6. PC drops to idle state - all LEDS still on, keyboard light off, display off. Powers off with a simple press of the power button

It can take up to 20 tries to get the PC to reboot...which is why I'm wondering if it might be temp related. ANYWHO....WhoCrashed shows mainly VIDEO_TDR_ERROR and other GPU/Driver related errors. Event Viewer is mostly inconclusive but will sometimes show video issues too.

I spent some time debugging and monitoring with GPU-Z, and I noticed that PerfCap was showing Pwr/Vrel a ton when under load before the crashes. 

As far as temps, CPU is chilling at low 50's, GPU temps spike up to 75-80C under max load. I'm curious if the RMA replacement might have bad thermal paste/pads and some components are overheating. I might take it apart to check in the next few days.

To help confirm it might be GPU I tried a friends 3080 and the PC was running much better, but still felt somewhat unstable at least in Fortnite (FPS drops every 2-3 seconds from 100Hz to 30Hz, some lag). With their GPU, GPU-Z was showing a ton of Vop/Vrel issues moreso than Pwr. FH5 ran fine though, no issues.

So I'm just curious what is causing this. I've tried literally every option I've found online and maybe half a dozen not listed above. I don't want to keep having Dell support send parts out but they don't seem to want to take time to debug my system before just shipping parts out. Would love some help!

Audio crackling/high latency with my old 3080 and RMA'd 3080 (since day 1), but not with friends 3080.

Below is a capture from GPU-Z right before the screen flickers and the PC crashes to black screen/idle.