ROG Xbox Ally Xhandheld screen stays black, works on external monitor, and Xbox full-screen experience is missing

My ROG Ally is having a weird issue and I’m trying to figure out if this is a software problem or a hardware/display problem.

When I turn it on, the built-in screen stays black. But if I plug it into an external monitor, I can see Windows, log in, and use the device normally on the monitor.

The other strange part is that the Xbox / handheld full-screen experience seems completely gone from Windows now, not just disabled. The Xbox side of the device looks glitched out and it feels like it is booting into a broken desktop mode instead of the normal handheld experience.

What I’ve already tried:

- Win + P display switching

- Win + Ctrl + Shift + B graphics reset

- Rebooting with and without external display connected

- Looking for Full Screen Experience in Windows settings, but it appears to be missing entirely

Since the device still works on an external monitor, I’m not sure if this is:

- the internal display failing

- a bad update

- broken Xbox/Gaming Services software

- some kind of driver or firmware issue

Has anyone had this happen on their Ally?

Especially curious if anyone has seen both of these issues together:

1. black internal screen

2. missing Xbox full-screen experience / glitched handheld UI

Any fixes before I go nuclear with reinstalling Windows or sending it in?