Area-51m, crippled by DPC latency

A while back I had a heatsink fail on my Alienware Area 51m (RTX 2080) and had a technician come out to replace it under warranty--the system is still very new. Immediately after he worked on it (as in, day of, first boot) the audio on the system developed a pretty annoying stutter / popping audio issue. At the time it had been a nightmare trying to get Dell to fulfill the warranty and I was just thankful the thing worked at all, so I let it be.

Last week I got tired of it and figured I would try diagnosing it. The issue seemed to be DPC latency spikes, and the main suggestion on that is generally "update drivers," so I started with updating my NVIDIA drivers (along with HD audio, etc.) with the belief that it would be easily rolled back if it was worse. Immediately after, the entire system slowed to a complete crawl and the DPC latency became so horrible the system is effectively unusable--it's running games that were 90fps at 5fps, it can take twenty seconds to open a file explorer or nearly a minute to open a single web page. It never lessens, the machine is now slower than my $100 chromebook at all tasks.

Amazingly, a total hard drive wipe and Windows 10 reinstall has done nothing to fix the problem. The laptop is unusable.

Things I've now tried:

• Total hard drive wipe and reinstall

• Every kind of check and diagnostic I can find (hard drive, ram check, every windows diag tool I've heard about, dxdiag), all of which turn up nothing

• SupportAssist diagnostics, which show nothing

• Disabling every single device in device manager that is not absolutely system critical

• Driver updates for every device in device manager

• Driver rollbacks for battery, sound, usb and display drivers

• Multiple alternate versions of NVIDIA drivers installed after wiping display drivers

• All sorts of tiny individual suggestions from the web around things like battery disabling / drivers

Nothing. Zero effect anywhere. The system is completely trashed and I cannot figure out where it could possibly be coming from.

LatencyMon results:

https://imgur.com/a/KIYRKAU