Rooting Google Pixel 4 XL

You must have Full OEM Unlock and USB Debugging (Preferable) to be enabled in the Developer options!

First of all download magisk from the official github and install the apk on your phone Download the stock firmware and extract the boot.img from it

copy the boot img to the device and enter magisk app

press on install and select the boot.img to patch it. The output boot.img copy back to the PC. enter the fastboot mode

and flash the img

fastboot flash boot magisk_patched.img

Now enter magisk and click on the button in the additional setup message and after a reboot - success !