OnePlus 8 pro bricked

-blackscreen after boot, “power off and restart shows up after holding power off button” (SYSTEM UI Won’t load up)
-can get into fastboot
-phone doesnt show up in device manager (com empty) tried rebooting,…
-no twrp
-tried to install stock firmware, still got the same blackscreen issue
-in msm there are no ports shown

-rooted via magisk

update 1: after trying flash stock firmware I am getting “Flashing is not allowed for critical partitions” and “Partition not found”