Getting my *** handed to me.. these damm brakes

But like OP. Bleeding alone doesn't fix. Or in my case. Doesn't fix for long. It progressively gets worse. Something is certainly sucking? (Sorry for the pun)
FWIW...I had the same issue. 4-piston K-H disc's up front with drums in the rear. No amount of bleeding helped...pedal always went to floor even though I was getting no aur out of the rears. Changed the rear wheel cylinders to new and....bingo, I quickly got a hard pedal. Not sure if the rear cyls were sucking air on pedal release or what but the new ones solved the issue.

Good luck 'cause it's little problems like these that stop you dead in your tracks!!