You said root permission is well granted, but app not showing properly? Try ask in the ROM you use to see if anyone had the same problem. Or ask Magisk developer in github and report issue.
I did not encounter this problem, so can not help you.
disable lockscreen pin, fingerprint, or patern.
Is there any different process for non global version, poco x3 pro bought in the ukAre you sure your phone is Global? Which country?
What version of MIUI?
How did you flash your boot image?
What partition did you flash the boot image into?
Were you using this one? If yes, flash the boot.img from here into your phone boot partition and see if your phone can boot up.
Boot your phone into Fastboot or TWRP. If you can, there's still hope. Do the step in above Unlock bootloader step 18.
ArrowOS as example: Download on PC Official ArrowOS -vayu ROM for POCO X3 Pro [direct link here].
Did you lose anything by unlocking bootloader? Like Widevine or something. Also, any special partition or file one should backup before unlocking (Not counting user data)? In Sony phones user have to backup TA partition or they will lose some features.
Thanks in advance