The best mattress you can afford is the single best investment you can make in your life. You spend 1/3 of your life asleep. Getting more high quality sleep has a direct impact on your mood, general health and personal productivity/effectiveness.
As someone who has trouble sleeping I've found what I sleep on seems to make surprisingly little difference as long as it isn't causing pain. Also, the breathable thing is likely a difference between cold sleepers and warm sleepers; as a cold sleeper I use a waterproofing layer and prefer that to a breathable mattress.
I like modal sheets which run very high in absorption, so perhaps covering with extremely breathable bed materials makes a difference.
I bought a high-quality memory foam mattress from a major brand and don't have these issues. There is some "tech" associated with mattress construction to counter these potential problems. One of the best purchases I've made.
I think y'all are being taken for a ride by the mattress industry and are paying for it not just with your dollars but also with your back health.