If you have a micro SD laying round, simply install this image on the uSD.
Using Method 2 to install it to your uSD
https://endeavouros.com/endeavouros-arm-install/
Then insert the uSD into the PBP uSD slot and boot the laptop.
PineBook Pro always looks at the uSD slot first. If there is a bootable device present, it will boot from it. If there isn’t a bootable uSD present, it looks at the eMMC connector for a bootable device.
So if you install to a uSD card, and put it into the uSD slot, it should boot into EndeavourOS.
If this is the case, then the hardware is OK and likely the eMMC is corrupt.
Pudge