Air suspension question

[leafsrule531]

Hi everyone - I have an 07 x5 3.0 with 3rd row seating so definitely have air suspension in my car. The rear of my car feels very harsh while driving (I don’t have rft tires either). The front feels fine over bumps. I recently changed the shocks on the car but never changed the air bags for the suspension.

I also have been noticing for the past few months when I leave the car overnight and come back the next day - it sags to the bottom but then when I turn the car on it seems to pump up and come back to level.

My question is, does this mean I have a failing rear air bag suspension? Would replacing the bags improve the ride quality in the rear or do the air bags have no correlation with ride quality on only self leveling ?