@dh297
Dear dh297. I just received the FP4 abd by default Android 13 is installed. I began the unlocking steps and operation from a windows 10 desktop. Don't forget to install the special google driver for usb in w10 upgrade system interface (windows key+i)
UBport has began the installation operation and after a rebootibg of my device it loose the USB connexion.

So screen I see on my device is the recovery screen of ubport.

I understood that the real problem was loosing usb connexion.

I ran 5 time the process after recovery and 5 times it failed.

Finally I decided to test it through my linux desktop and That's IT! It works perfectly

So android 13 is OK! But try to install with the ubport under a linux desktop and it it was easier than from windows because you just have to install a few linx package then the rest is natively supported to run the automatic installation.
Now it's success!!

Good luck