Rooting Lenovo tab M8(FHD) That was Upgraded to Android 10 I had rooted this device when I bought it and it was on Android 9 (See Here)
Now I upgraded the device to Android 10 with Lenovo Smart and Rescue Assistant. When I try to root it the same way I get a bootloop.
This is what I have tried.

I tried using the Magisk Manager for Canary as per this info. This didn't help.
I tried to flash the vbmeta.img with the option --disable-verification as per this post on xda. This did get me out of the bootloop but after it booted I didn't have root.

Any suggestions on what else I may try?
Thank You,
I finally figured this out and got root. You need to flash the patched boot image file after you flash the vbmeta.img with --disable-verification.
Here are the steps I did to get root.

Copied boot.img from the firmware to my device.
Downloaded Magisk Manager. (The regular version, no need for the canary version).
Patched the boot.img with magisk manager.

Clicked on Install on the righthand top in magisk manager.
Clicked on Next Righthand top.
Selected Select and Patch a File.
picked the boot.img file I had copied in step 1. Magisk manager patched the file.


Copied the patched file pack to my PC.
Booted into Fastboot.
(Flashed the patched boot image to my device fastboot flash boot path-to-patched-boot-image) I don't think this is needed here but it is what I had done.
Flashed the vbmeta.img from the firmware with the option --disable-verification. fastboot --disable-verification flash vbmeta path-to-vbmeta-imageIt does not need to be an empty vbmeta image.
Flashed the patched boot image to my device fastboot flash boot path-to-patched-boot-image. (A second time, but as mention before I don't think the first time is necessary).
fastboot reboot.

...And now I have root.
Disclaimer use this info at your own risk. I take no responsibility for it.