man are you serious, nitroflare filehosting? it has 20 kb/s download speed and must wait a few hours to be able to download a second file...you could have done better than that
anyway, after all the fuss with downloading I installed your latest kernel and I couldn't obtain root privileges no matter how many times i installed different magisk versions after your kernel, titanium backup, mtweaks, adaway didn't even started to name a few...
back to my good old Fusionkernel 1.2, magisk 20.4 imediatelly after that, and bingo everything back to normal!
too bad, phantom kernel used to be good in the past...
I really like these kind of posts... they make me think twice about how much time I've spent into this project and if it was worth it.
I guess it's hard to read thread for some answers, but no matter...
About solving you're issue with root:
Did you try?
1. Complete uninstall Magisk from Magisk manager and wait for reboot (don't reboot, just wait to reboot).
(enter your custom recovery)
2. Flash Phantom kernel.
3. Flash Magisk.
(Optional: clean dalvik cache and cache. This is not needed for kernel, but sometimes it helps your ROM because of the modified files).
4. Reboot.
(Wait for phone to compete boot - you'll feel 3 vibes when that is done).
PS: To report an bug, issue or other whatever kernel related problems you have, please describe and give details about the ROM you're using (at least) or helpful stuff like logs or how to reproduce the issue (in some cases).
PPS: To understand why Nitroflare, read previous posts about it. Maybe it will make things more clear for you.