I resolved this issue just now, how I did it follows the device behavior, and what I tried before it worked.
Had this issue this morning with my Quest 2: Grey screen, and the only things visible in the headset were the Oculus Logo, Oculus logo progress for re-centering, and three light grey dots (indicated loading).
I tried: 1) Power cycle with Hard Button on Headset, this did not resolve the issue. 2) Android-based Oculus App Factory Reset after not being able to access Factory Reset from within the headset. This de-coupled the device from my account, but did not resolve the issue.
What worked for me: Once I was sure that the headset was powered OFF, which was a challenge overcome by multiple attempts to power down through very long (10-15 seconds) of the hard button on the headset, I pressed the power button AND Volume Minus "-" buttons from a powered down state. This brought up the in-headset OS menu, which allowed me to Factory Reset.
Note: My first successful attempt to Factory Reset, the device still slipped to grey screen when I was delayed in linking the Headset to my Oculus app, so I Factory Reset again, and performed the pairing quickly, without the headset screen powering down. It can detect when it's on your head. Now to download a bunch of my favorite apps. Best of luck everyone!
While it was not acknowledged by support, I think my account was part of a test for some new firmware (they wouldn't tell me even if they knew).
I came to this conclusion after purchasing a brand new Quest 2 headset, and noticed the same behavior the following day after linking it to my account.
I haven't had problems with it in the past week, so maybe they changed the firmware, or edited my account out of the "test".