This will become increasingly important as Google has boiled the frog too fast while trying to force its new store policies + banning sideloading; however, all of the pieces are now in place for them to try again in a year or 2, which history shows us they will. It’s certainly time to start toying with Linux phones if you haven’t already. This year I picked up an Xperia 10 to flash Sailfish OS on—which has rough edge…
What I never get is: why not prepare to fork AOSP? I like the security model of AOSP :-).
eOS is basically what you are looking for for most phones or GrapheneOS (pixel only)