Time to get rid of the "S" Mattress - Will Latex suit me?

My wife and I purchased a King Sized mattress when we got married about 5 years ago. Needless to say we went to a brick and mortar store, and bought one of the cheaper kings we could find with a “euro top”. Now fast forward five years later and you know the story, the foam is shot/flat, and the springs are sagging. Between then and now I’ve educated myself a bit about mattresses as a result of buying a bed for our son, he sleeps on a MyGreenMattress Pure Echo, with their 2 inch plush dunlop topper.

Sleeper details: Me: 6 ft 170 combo back and side sleeper. Wife 5’4" 160, combo stomach and side sleeper.

My only experience sleeping/laying on latex is on my son’s mattress (Pure Echo is a true firm mattress coils/wool only mattress, the dunlop topper is 14-19 ILD, 55 density), and laying on a Southerland Wrangell at a local box store (3 inch copper infused Talalay top, unknown ILD). The Southerland Wrangell 3 inch Talalay honestly felt a little too soft for me, where wasn’t much support, just “fluffy”. My son’s Pure Echo mattress with the super soft dunlop topper gives me some back pain in the upper middle of my back. I can lay on his mattress without the topper and have no pain, but as soon as I add the 2 inch soft topper, I get a little upper middle back pain. It’s odd. Perhaps the topper is too soft for me, but with such a firm mattress underneath I wouldn’t think that a soft 2 inch topper would cause back pain.

QUESTION: Does the fact that I’m getting back pain with a 2 inch soft (14-19 ILD) topper mean that my body just doesn’t like dunlop latex? I can literally lay on that same mattress without the topper and no pain.

My wife prefers soft/pillowtop like comfort. I prefer a little bit more of a medium firm. If I’m honest I probably like the hug of memory foam better than the cradle of latex, but I’m wanting to avoid all the bad foams and chemicals, and invest in something that will last longer than 4-5 years before going flat. This has led me to targeting a latex hybrid mattress, and I’ve narrowed things down to the EcoSleep Hybrid, the SleepEZ Hybrid, and the Birch mattress. I’ve had some conversations with SleepEZ (great customer service) and they feel the “medium plush” side of the Hybrid they offer would be a decent fit for us based on our sleep styles and weights.

QUESTION: Anyone in roughly our weight ranges able to comment on the feel of the medium plush side of the SleepEZ Hybrid? Again, we’re both about 160-170.

Thanks so much!