No Goldilocks "just right" here!

My husband is able to fall asleep on this bed but wakes up with back pain and never found his sleep number. When I try to adjust it for him he says it's fine anywhere from 85-60, though usually has me turn it down for him after a few minutes at 85. I didn't feel comfortable until around 30 but would usually turn it down to 25 in order to fall asleep. From 100-45, the change in each 5 step increment is very small. Letting air out for ~1 second each step. From 45-35 ~4 seconds each step. Going from 35 to 30 ~7 seconds. 30 to 25? ~13 seconds and there is no in between. I don't feel very comfortable until around 30 but usually end up going down to 25 in order to fall asleep. Then I wake up sore and achy. I can't find a comfortable number on this bed at all. I wake up multiple times a night with shoulder pain or neck pain trying to find ways to get more comfortable. At first I thought maybe it was my pillow and have bought half a dozen pillows with no luck. This is the worst (very expensive) purchase we have ever made. It seems this model has been dc'ed and it's obvious why. We didn't realize soon enough - I thought it'd just take some getting used to for me, which was my second mistake but it has gotten worse over time as well. My husband thought he liked it, but after we went 2 vacations in a row where he woke up with no back pain after sleeping on mattresses in nice hotels- and one night in a regular business class hotel when we went to see his daughter when she was having a baby, he realized the bed is definitely what's been causing his back pain. My husband is on the heavy side (~250 lbs) and I fluctuate between 105 - 113. The side support on his side is smashed out terribly. That happened soon after we got it but I didn't realize right away how bad it was. Bottom line: after less than 2 yrs of buying it, I am now actively researching new mattresses as quickly as possible and trying to figure out what to do with this very expensive mistake. Don't know whether to just trash it, give it away or what.