Dragging brakes/ crappy pedal feel

Ive had an on going issue for a few months now and am out of answers, going slow you can hear a brake groan like its a warped rotor and the pad is dragging, as well as you have to push though a 2 inch air cushion before the brakes work. I first thought it was a bent axle or warped rotor because it was only one wheel doing it, I replace the rotor and scuffed the pads. That work for a day then it came back but at a different wheel, and now all 4 wheels do it not all the time but one time L rear next R front, some times you hear it from the front and back at the same time. So far I have replaced the RR rotor, turned both front rotors (re scuffed the pads) and bled the system 5 times, I have brand new clean fluid coming out of the back calipers. The biggest help is bleeding them that makes the pedal feel great but it only last a few days then its back to feeling crappy. I am out of answers, bad M/C, cracked vacuum line, a frozen caliper, bent a hard line to far and making a pinch point? Any thoughts or things to try Im all ears. Only thing done to my brake system is longer SS front lines for my lift, each side has a different brand but Ive been told a few times that wont make a difference even if the ID is slightly different.