I've been into mattress design as an amateur for 20+ years. Mattresses are one of the most highly marketed items yet misunderstood. My first "discovery" involved buying a Latex mattress from a local factory. I used it as is for awhile and it did not get hot like foam. However, after a few months I added 2" of pretty dense memory foam. This is when I began to understand the dynamics of a mattress. I ended up buying a Tempurpedic. It wore out, they all do.
After that I stepped up to a Sleep Number that I bought used for a good price. It had been in a guest room and seldomly used. It was clean enough for that to be believable. It was a low end model and if you know anything about these companies, they have a long list of 'upcharges' which amount to nothing more than more layers of various foams and filled cotton covered inserts. Each helps but the costs for these upgrades is where the profit is.
The point being whether you have a water bed, an air bed, a layered foam bed, or a spring mattress, you need to find the toppers that work best for you.
I think the perfect bed starts with 6" of Latex covered with a 2" layer of really dense foam and 1" of the lighter foam, egg crate or not. Then the highest quality of mattress cover like feather or some really trick synthetic. For some time I was using an
Ogallala. That was wonderful but they also wear out and they are not really cleanable. Ogallala is not the only company that makes a feather filled topper, so shop around if you like this idea. And you can skip the 1" layer if you go with a feather topper. They sleep nice and cool.
Of course, YMMV. And that's the point, again, get something you can work with until you get it right. Recently I took the Sleep number all the way down to the air chambers and bought my own foam layer (it requires a 3" which is in conflict with my
ultimate bed) and installed that in the zippered pocket above the chambers. I wish I had gone ahead and bought some Latex for that under layer but Latex in a queen size is a LOT of money.
After that, there is one more zippered pocket designed to receive a 1 to 1-1/2 layer of your choice. That's the one you will feel when you lie down more than other aspects. Yes, you can adjust the air pressure but it doesn't do much more than create a hammock. That's because most of your weight is from your neck to your knees, if that far. It doesn't work like water.
So, my conclusion is to start with a Latex base and work up. I have an articulated frame so many mattress materials, like a spring mattress are not suitable.
And if you've ever slept in a real feather bed, you know what I'm saying about that layer just below your regular washable mattress cover. However, they require daily complete shaking and fluffing. I'm not stripping my bed every day so that's simply a once in a long while luxury.