I’m glad you’ve gotten relief, and really sorry you tried all those other things first. Did you happen to try a latex mattress? They seem “foamy” but they are much more like spring mattresses than they are like memory foam. Basically the more compression it is under, the more resistance there is, exponentially, whereas memory foam compresses linearly. My wife and I switched to Latex and it made a massive difference in our sleep quality and how we feel afterward. The memory foam mattress made us hot and made my back hurt really bad. Now I wake up and I feel refreshed, and I sleep an hour less but get the same quality of deep sleep as before. You may not want to tamper with anything since you’ve found a solution, but I wanted to mention it because it does give more pressure relief than an inner spring but with more support than memory foam. They’re expensive and heavy though.