helpos When I was trying to get back into the bootloader screen, I noticed that my Pixel might have done a factory reset on its own (I now have to select language, time zone, etc. — just like when I first turned it on).
Unlocking the bootloader wipes the user data partition. Also, locking the bootloader wipes the user data partition.
helpos Does it mean I have to start completely from scratch (except the unlocking part), or should I be fine just hitting “Flash Release” on a new device?
If launch the web installer from some device other than the Chromebook, you will need to do basically the entire process from the start. In particular, you will need to download a release, and you will need to put the device into fastboot mode.
Basically, always start from the beginning ("a very good place to start").