😁 Looks like you've tried everything. Here are a couple of more things to try. I know you've deleted and reinstalled the Horizon app on your phone. Try going into the app settings on your phone and delete cache and try again. If it doesn't work try deleting the cache and the data (deleting data will mean it forgets everything so you'll set it up again.) Final option, in case there is a, software glitch on the headset itself, connect your headset to your pc and run the Meta Software Update tool. If there's been a glitch in the software it should repair it.
Here's the link. I hope you can get it fixed and let's know how it goes. 🤞
https://www.meta.com/help/quest/software_update/
Just choose your device from the list and follow the instructions from there.