Essential ph-1 phone stuck in boot loop

Not sure a lot of people here have an Essential, you may want to look at XDA or even reddit. I had one 'til just recently, it started doing too many stupid things and I knew its days were numbered. Ended up getting a Pixel 3a that I neither love nor hate. I loved my Essential and miss it

 

Can't you just force a restart (press and hold the power button) and then use some key combination to boot it into recovery mode? If the bootloop is due to corrupted data then a factory reset from there should fix it.

If the firmware is corrupted then a reflash is needed, but most phones don't require the bootloader to be unlocked in order to flash official stock firmware (and I'm sure Essential provide factory images). It's only unsigned stuff (custom ROMs or recoveries) that generally requires unlocking, and indeed with some phones you have to actually lock the bootloader in order to flash stock images.