How Air: cameras in locked "error state"

Hello! I have a Chuwi Hi9 Air tablet since a few days ago. It wasn’t used before and I’ve only started setting it up, but I’m already having issues with it. The camera worked for 3 or 4 days, and now out of the blue I’m getting a “error state” popup message when launching any camera app.

None of the two cameras work anymore. Even the Camera 2 API probes return no hardware.

I’ve tried a full factory reset, didn’t work. Upgraded the firmware to a newer Android version, still doesn’t work. Fully erased the tablet with Mediately SP Tools to flash the stock firmware and downgrade it - still broken.

Any help?