My Pixel 9 Pro running the latest stable release is bricked. It may or may not be user error to some extent but I figured I would share so others don't make my $1500 mistake(s).
I set Fossify Keyboard as my default Keyboard on the Owner profile. I also chose to use a password as the unlock method for the Owner profile.
I may or may not have disabled the default Keyboard app. Honestly, I don't remember.
When I restarted my phone the following occurred.
https://drive.proton.me/urls/T03N15QNR0#tT96D2lQcGpl
Link contains the mp4 video file.
As the video makes plain, it appears to be impossible to enter my password via the Keyboard or change said Keyboard. Considering that I had already set USB to charge only and the boot menu is locked, this seems to be one of those impossible to recover from problems.
My best guess is that I did disable the pre-installed Keyboard for whatever reason and for whatever reason the new default (Fossify Keyboard) can't start/be used until after first unlock.
Essentially, my guess is that only the pre-installed keyboard can be utilized before first unlock but if it is disabled in the Owner profile then it can't be used. And without a keyboard, it is impossible to enter the password.
On the other hand, if you examine the video at approximately the 41 second mark you can see the (very temporary) keyboard selection menu and it offers the standard keyboard.
This is a screenshot of that frame:
https://drive.proton.me/urls/CMHG1J9AQW#1vnxdc7th7g6
So it's either:
1) user error of some description (my current best guess), although this is an error that shouldn't be possible to cause.
2) an issue with the current latest stable version of Fossify Keyboard. This seems unlikely or it would be a more widely known issue.
3) an issue with 2024102100 that somehow hasn't been noticed yet.
4) some weird interaction between Fossify Keyboard and the Graphene release.