DW and I could not handle any type of foam mattress. Sleep Number if you can afford to put $2K into a mattress in your RV. We went with Verlo, a franchise that has 47 locations nationwide. They built a custom 72" x 80" RV King for us for about $700 and we absolutely love it.
https://verlo.com/
Bob & Diane Sorrells
2018 MHC 305RL
2016 GMC 2500 SLT Crew Cab 6.0L Gas w/ Timbren Suspension Enhancement