I’ve found inflatable mattresses to be universally rubbish.
So did I, until we got an Aerobed. 7- 8″ thick double mattress. Including the pump, it folds up into a bag the same size as 2 thermarests. very comfy, taut, and tunable, not wallowy unless you want it to be. Doesn’t lose air. Had it for 4-5 years.
Not the cheapest, but it paid for itself very early on. We took it to Norway for 2 1/2 weeks’ car camping, expecting to pay for a night or two’s accommodation at some point. We didn’t because the bed was as comfy as we’d want it to be, and we could wake up in a private “room” by a lake.
Fitted sheet, feather pillows and down duvet ftw – again, not much bigger than 2 big sleeping bags.
blows up to fit the back of the mondeo too.