It will disable incremental updates but as long as there is a flashable zip file of the full image you can update using that

You can also quickly unroot then do an incremental update and then use magisk to create a flashable boot image afterwards to re-root

This update doesn’t seem to remove any add-ons specifically but turns them off on more sensitive websites if Mozilla has not reviewed them.

It does look like there is an about:config option to turn it off, however it looks like this is most likely to be for bank websites etc. and only for add-ons not reviewed by Mozilla.

Currently, at least, ublock origin and most of the bigger adblock add-ons are reviewed by Mozilla and shouldn’t be affected