I had success rooting this device (Moto E6 Surfna) by following the "Boot Image Patching" method here: https://topjohnwu.github.io/Magisk/install.html
mingkee had success with the same method on the G7 https://forum.xda-developers.com/moto-g7/how-to/root-g7-magisk-t3907084
Summary:
1. Unlock bootloader, this can help https://forum.xda-developers.com/moto-g7/how-to/guide-unlock-g7-bootloader-t3906858
2. Download the firmware for your variant: https://mirrors.lolinet.com/firmware/moto/surfna/official/
3. From the firmware zip, extract the recovery.img
4. Install the Magisk Manager https://forum.xda-developers.com/apps/magisk/official-magisk-v7-universal-systemless-t3473445 on the phone
5. Push the recovery.img to the phone
6. From the Magisk Manager, tap "Install" then "Select and Patch a File", find the recovery.img and patch it.
7. Pull the patched img to the PC, Magisk Manager will put in /sdcard/Download/magisk_patched.img
8. Flash the patched img as recovery (fastboot flash recovery magisk_patched.img)
I used the recovery.img instead of the boot.img because the boot.img didn't work for me. Check out the "Magisk in Recovery" section https://topjohnwu.github.io/Magisk/install.html
Start the phone in recovery mode and Magisk will start the phone normally. In the future, the phone will need to boot in recovery mode to start Magisk. A normal boot will cause Magisk to deactivate.
Proceed at your own risk. I give no guarantees, implied or otherwise.
Also, I might've missed a step here or there.
Good luck, happy rooting.
mingkee had success with the same method on the G7 https://forum.xda-developers.com/moto-g7/how-to/root-g7-magisk-t3907084
Summary:
1. Unlock bootloader, this can help https://forum.xda-developers.com/moto-g7/how-to/guide-unlock-g7-bootloader-t3906858
2. Download the firmware for your variant: https://mirrors.lolinet.com/firmware/moto/surfna/official/
3. From the firmware zip, extract the recovery.img
4. Install the Magisk Manager https://forum.xda-developers.com/apps/magisk/official-magisk-v7-universal-systemless-t3473445 on the phone
5. Push the recovery.img to the phone
6. From the Magisk Manager, tap "Install" then "Select and Patch a File", find the recovery.img and patch it.
7. Pull the patched img to the PC, Magisk Manager will put in /sdcard/Download/magisk_patched.img
8. Flash the patched img as recovery (fastboot flash recovery magisk_patched.img)
I used the recovery.img instead of the boot.img because the boot.img didn't work for me. Check out the "Magisk in Recovery" section https://topjohnwu.github.io/Magisk/install.html
Start the phone in recovery mode and Magisk will start the phone normally. In the future, the phone will need to boot in recovery mode to start Magisk. A normal boot will cause Magisk to deactivate.
Proceed at your own risk. I give no guarantees, implied or otherwise.
Also, I might've missed a step here or there.
Good luck, happy rooting.