Sorry by solid I mean firm, not on and off but very confidence inspiring brakes.
I had avids before(not sure if I have metioned that !!) and the lever feel changed all the time from firm to spongy, from lots of travel to very lttile travel.
totally unpreditcable to be honest, a bit like the hopes I had too….
OP something does sound amiss with yours, It sounds as though there is still air in them if the lever comes back to the bars after a bleed ?
I dont want to teach you to suck eggs and my apologies if I do but it may be something simple like not leveling the lever out that you are missing.?
Have you tried new pads too?
EDIT.. you said the rear was giving you issues… have you checked the hose over to see if there is any damage or kinks to it?