Well what I do every-time a new monthly update is released is as follows -
1. Go to Magisk Manager -> Uninstall Magisk -> Restore Images.
2. Go to the System Update and let it download and install the new monthly patch.
3. Restart the phone.
4. Download the latest factory image from https://developers.google.com/android/images on PC.
5. Extract the boot.img from the .zip file.
6. Move the boot.img to the phone, open up Magisk Manager, patch it manually.
7. Move the new patched boot.img file back to the PC, restart the phone to the bootloader and then flash the new patched boot.img using ADB.
8. Restart the phone again and you're done!
The last post i write a EdXposed module to enable Soli.
Now I'm write a Magisk module to enable Soli without restart zygote,and reboot the device will keep Soli to enabled.
Please go to github and download this module ,the url is https://github.com/demj1206170/EnableSoli
and feedback if there have any issues.
U can do this with magisk Hide props conf.
U should install this module, then install terminal, type :
Add new props (u should choose it from the list) Add only this: pixel.oslo.allowed_override true
If the error states that it's not a Magisk zip, or invalid zip in TWRP, the zip is not packaged correctly. Open up the zip and you'll likely see a folder (probably named something like <nameofmodule>-master or similar, or something completely different). Take all the contents of that folder and repack it to the root of the zip and try flashing it again.