My Pixel XL bricked itself one morning due to a software update that triggered some kind of hardware bug. Great phone until that point, then poof, and it wouldn't even connect with a debug connection to my PC to replace the firmware or recover itself.
I've put it on a shelf until I can get time/money to recover the data from the flash, but lesson learned.
Regret to inform you that it almost certainly isn't a bug - the flash died. It's unrecoverable.
Large numbers of pixel 3/3xl's have started dying in the last year and it looks like it's the flash wearing out on all the early adopter/heavy user devices. This happened to me too.
I've put it on a shelf until I can get time/money to recover the data from the flash, but lesson learned.
I bought a Samsung.