New mattress

Our first mattress was Dunlopillo and it lasted us 25 years. The only reason we replaced it was because the fabric had worn through.
Since then we have had dense form mattresses mainly because we couldn't afford the price of Dunlopillo.
There's such an array of mattress types it can be confusing.
We wanted a new mattress for our spare bedroom. Daughter offered theirs which was still new because they were going super king size.
The mattress was a sprung firm/hard which I thought wasn't comfortable so I bought a good quality topper and it is perfect for son and wife when they visit.They have since visited and remarked how comfortable the mattress was.
I think you need support and comfort and you'll find just lying on one in a showroom is not enough time to decide.
Some companies now allow 30/90 day trial periods if you are not sure.
Best of luck

I used to work in the furniture industry.
One of the best mattresses we sold is the Waterlattex, it’s very supportive, has a summer side and winter side.
I have slept on ours for some years now and will shortly replace with the same.

Mattress in box