Quest 3 OpenXR Broken After Update: Gray Button, Yellow Borders, UEVR/Praydog Mods Fail

I have a Meta Quest 3 on Windows 11 Pro 25H2 (Ryzen 7 7700, RTX 4070 Ti Super, 32GB RAM).

Everything worked perfectly for almost a year. After the latest Meta Quest PC app update (early December 2025), OpenXR stopped working for VR mods:

"Set Meta Quest Link as active" button is grayed out and unresponsive (even as admin).
UEVR and Praydog RE VR mods fail with "OpenXR not found/not loaded".
Luke Ross Real VR mods (non-OpenXR) still work fine.
Thin yellow borders now appear around my monitor when Link mirrors the desktop (new since the update).

Already tried:

Clean reinstall of Meta Quest PC app (deleted all folders in AppData, Program Files, etc.).
Manual registry fix (ActiveRuntime correctly points to oculus_openxr_64.json).
Uninstalled SteamVR and Mixed Reality tools.
Disabled HAGS, repaired app, ran everything as admin.

OpenXR Tools detects Quest 3, but mods can't load OpenXR. I suspect the new Graphics Capture API (yellow borders) is conflicting.

Please see attached screenshots: