Solution: I freaking rolled back my Nvidia drivers and it solved the problem.
This is a new issue after a few weeks of using Oculus Link without any problems.
Upon trying to load through Link, the headset goes into the black loading screen with three dots. After about 15 seconds, it returns straight back to the Oculus Quest Home screen without any errors. After this, both my PC and Quest headset act as if I've reconnected the link cable -- whereas my computer pops up with a "Can't Find Device" and my headset displaying an "Oculus Link Available in Settings" message subsequently. The same behavior results from using Air Link.
HP Omen 15 Laptop (Ryzen 5 4600h, GTX 1660 Ti, 16gb RAM)
Oculus PC Software - On version 126.96.36.199.502
Oculus Quest 2 - On version 188.8.131.52.350.300158191
What I've tried so far:
Restarting PC and Quest 2 multiple times
Trying builds v30 and v31
Reinstalling the entire Oculus PC Software
All Refresh Rate options
2 Different Link Cables
Ideas that I've found from other posts with similar issues:
Downgrading my Quest 2 firmware to match my PC's Oculus Version
A whole entire clean install of Windows
Where I think the issue might be:
Oculus v30 updates were dropped
My PC's bios was updated
I updated to Windows build 21H1
I updated my Nvidia Game Ready drivers
The versions between my PC and Quest are different (refer to above).
So there are quite a few places this issue could lie.
Ahh sorry only just seen it said you tried the refresh rates. Mine connects fine, but im having another infuriating issue. It keeps losing tracking and guardian. I cant even play a game anymore as its every 20 seconds it loses is and returns to trying to create new guardian. Its only happened since v30 so its evidently a software issue but support have been useless