Well I have probably had 6 beds since this happened. I cant suggest a specific and I feel we are all different too in terms of how we sleep with the condition etc. Some things I look for is height of mattress, type such as pillowtop,etc. Also even items like sheets and blankets can flare me up in terms of texture and weight. You can also try the toppers for beds.
I do feel my whole body not just the rsd areas responds odd to temps. I seem to process what ever the temp is more so if it is cold I am frozen,hot I burn or swell etc.
I see you are new and welcome though sorry about the condition. If you feel comfortable you may want to share more.