Use MiFlash and reinstall latest MIUI global OEM ROM for your phone. So in other words go back to stock.I have xiaomi 10s. I updated to 13.0.6 previously and then downgraded to 12.5.3 using fastboot (with data format).
But after downgrading, the phone is always in blackscreen, but the sound is ok which means everything except screen is still functional.
Flash Xiaomi.eu 12.5 again.
Downgrade can be the issue. Possible kernel compatibility or something.