1. download stock firmware
2. unlock the bootloader
3. flash stock firmware
4. install magisk apk
5. extract boot.img from downloaded firmware
6. copy boot partition into the phone meory & then open magisk app & patch that boot.img
7. copy patched boot.img on desktop
8. download & extract platform tools & open command prompt inside platform tools
9. power off phone & keep holding volume down button & insert data cable to boot into the fastboto mode
10. flash patched boot.img by using command fatsboot flash boot (here drag & drop patched boot.img) & then press enter
11. reboot phone into recovery mod eby using buttons & factory reset
12. once full load.. connect to wifi & update magisk app or reinstall magisk apk.
13. done
here is full visual guide
2. unlock the bootloader
3. flash stock firmware
4. install magisk apk
5. extract boot.img from downloaded firmware
6. copy boot partition into the phone meory & then open magisk app & patch that boot.img
7. copy patched boot.img on desktop
8. download & extract platform tools & open command prompt inside platform tools
9. power off phone & keep holding volume down button & insert data cable to boot into the fastboto mode
10. flash patched boot.img by using command fatsboot flash boot (here drag & drop patched boot.img) & then press enter
11. reboot phone into recovery mod eby using buttons & factory reset
12. once full load.. connect to wifi & update magisk app or reinstall magisk apk.
13. done
here is full visual guide