Flash ROM, boot the rom without Magisk.always bootloop after flashing magisk (15.3, 16.3 and 16.4)
with magisk 15.3 it's fine on the first boot but after reboot once again i got bootloop
Flash twrp again (because it is getting overwritten without Magisk at first boot), boot twrp immediately, flash Magisk.
Should work fine,i always have bootloop issues if i do not boot the rom first without Magisk.