Those builds have 100% identical hardware interface / kernel. Focal, Bionic and Buster differs only in application layer / user space / packages versions. They are identical to their official counterpart so you can ran 3rd party programs without adjusting things.
You can boot something from this OPi3, Android? When SD card is not present? Did you try changing power supply and booting without attaching anything else? It looks like some hw defect, where we can't do nothing much about.
