Same issue here. I replaced the mattress setup in a guest room with an adjustable bed. It has a decent quality mattress with adjustable base. While the adjustable part is ok, the mattress doesn't give the same support/feeling as a mattress on a foundation. Maybe I could get used to it if I gave it time. Anyway, I went back to using my wedge on the king, which I sleep well on. Relax the Back makes them in standard and wide sizes. Very comfortable.
https://relaxtheback.com/products/contoursleep-side-sleeper-bed-wedge?_pos=6&_sid=de9eb23bd&_ss=r