Unfortunately I'm in the same condition as you with the xiaomi 12. it stopped working, charging only. if I connect PC or USB drivers the power light turns on but nothing more. Restored, updated, only the clean installation I couldn't do because it doesn't connect in fastboot mode. I've tried everything. There are other people in the same condition, the last chance is to replace the USB charging bar. Let's see what happensI set the data transfer in developer option, but dont pop up this window.