That screen/expansion device doesn’t have an eeprom in the correct location to read on bootup…
Grab the buster image:
Then downgrade to the older 4.14.x based image:
sudo apt update
sudo apt install linux-image-4.14.108-ti-r143
sudo reboot
Once booting with 4.14.x set this in /boot/uEnv.txt
dtb=am335x-boneblack-bbb-exp-c.dtb
Regards,