Hi mg517,
You’ve probably read this already but just in case … the first step is always post #1 here. This is the most important post on the forum for anyone who is looking for a new mattress and will help you with the basic information you need as well as what to focus on and what to avoid completely.
As you will see … the choice of materials or components is a personal preference and there are no better or worse materials … only versions of every material or component that are higher or lower quality.
No matter which materials or components you choose or prefer (latex, memory foam, innersprings, polyfoam etc) … the goal is always to choose a design that provides the best balance between pressure relief and neutral alignment in all your sleeping positions. There is no intrinsically “right or wrong” or “better or worse” combinations … only the combinations and designs that best fit your unique needs and preferences. Don’t forget that every layer of a mattress interacts to different degrees with every other layer of a mattress and with the unique body type and sleeping style of the person that is sleeping on it. This is why a topper on one mattress may work well but not work well at all on a different mattress because both the topper and the mattress can interact with each other and with you in sometimes unpredictable ways when you sleep on it and the same topper would be fine on another type of mattress.
There is also a wide range of different sensitivity levels to the basic needs of a mattress which is pressure relief and neutral alignment of the spine and joints and some of us are closer to the “I can sleep on anything” end of the scale where a wide range of mattresses will work well while others are closer to the “princess and the pea” end of the scale where a much narrower and more specific range of designs are the only ones that will work best. This is where very careful testing and good options to make fine tuning adjustments after a purchase (rather than completely exchanging a mattress and starting over again) can be very valuable.
In most cases … the knowledge and experience of the person you buy from can be a major part of a successful mattress purchase and “finding the experts” is usually a much more effective approach than “becoming an expert”. This is part of why I normally suggest staying out of chain stores where the knowledge level is usually very low and staying away from major brands where meaningful information about their mattresses or the ability to make adjustments after a purchase is usually missing.
So I would follow the steps one by one and focus on “connecting with the experts” and then working with them so they can help you resolve what clearly is a difficult challenge. You have many very good options in the New York area and the better ones I know of are listed in post #2 here and there is a more categorized list with more detailed descriptions of many of them in post #7 here.
Sometimes it can be a good idea to do a complete re-set of your fundamental approach and underlying assumptions about buying a mattress and without excluding any possibility (except the retailers or manufacturers that are not transparent about the materials in their mattresses or mass market retailers which are more focused on profit margins and commissions than helping and educating their customers) start from the beginning again with a new and different underlying approach that can greatly increase your odds of success.
Phoenix