Stuck on Redmi logo system load screen or first Redmi logo?
"Stuck" on load screen => It can takes 5 to 10 minutes to boot after each update, that's normal.
"Stuck" on first boot screen => Should not happen, phone should reboot itself to Recovery.
Anyway, try without Magisk => Proper remove Magisk with uninstaller zip file.
Another question: Did you use K20 Pro to Mi 9T Pro conversion patch on 11.0.4?