WOW. Congratulations, your persistence paid off. 
The xf86-video-fbturbo-git is a ‘X.org MALI video driver’. The Pinebook Pro 64 has a Mali T860 MP4 GPU so I’m not sure why it is causing a problem. The T860 probably is the latest Mali GPU, so maybe xf86-video-fbturbo-git is old enough that it doesn’t support Mali T860?
Here is the list of packages that the EndeavourOS script uses.
You will see that line 8 is the xf86-video-fbtrubo-git driver. If you install again, after the git clone that downloads the script and support files, if vi or nano is available one could try deleting that line. Don’t comment it out with a #, actually delete the line and don’t leave a blank line in it’s place.
Normally dhcpcd is installed as part of the Archlinux Arm base image. How is the EndeavourOS script and it’s support files downloaded, on wifi or ethernet? Does the Pinebook Pro even have a ethernet port. It looks awful thin to accommodate an Ethernet jack. I know very little about WiFI, does WiFi utilize dhcp?
Right now, when the script gets to line 626 it assumes dhcpcd is installed and tries to use systemctl enable dhcpcd.service, as most SBCs have ethernet.
If they are downloaded via wifi, that means that the process for getting Archlinux base is not installing dhcpcd. So if dhcpcd is necessary, one can use vi or nano to change line 8 of the base-addons file from ‘fx86-video-fbturbo-git’ to ‘dhcpcd’
If dhcp isn’t necessary, we can put in the script a condition if the device is a Pinebook Pro 64, skip enabling dhcpcd.
Hope that helps, if I can help in any way, let me know.
EDIT:
Is the home of the EndeavourOS arm install script and it’s support files. It’s all written in bash, so easily edited to adapt to special needs. If any of you Pinebook Pro 64 laptops or RockPro64 SBC pioneers have any questions on the script or support files, let me know.
EDIT #2
Arm wallpaper by @FLVAL . His wallpaper is 
In current US slang, saying something is fire is a very good thing.
Pudge