All RV OEM mattresses are junk. You can put a band aid on yours with a topper if you like toppers, I don't, or just bite the bullet and replace the entire thing.
I full time so a band aid wasn't my solution. A Sleep Number was. Much better and lighter also.
2006 GMC 2500HD CCSB 4x4 Duramax/Allison, Titan 52 gallon fuel tank, Prodigy Controller, B&W Companion Hitch
2010 Jayco Designer 35RLTS, Cummins/Onan RV QG 5500 EVAP, Progressive Industries EMS-PT50C, TST Systems 507 TPMS, RV Flex Armor Roof