Hi MattressNewb,
While I don’t have any specific suggestions or recommendations because there are too many unknowns and individual variables that are involved with choosing a topper (including the type and firmness of the mattress underneath it which can also affect the thickness and firmness of a topper that works best for any particular person) … there is more information about choosing a topper in post #2 here and the topper guidelines it links to that can help you use your sleeping experience as a reference point and guideline to help you choose the type, thickness, and firmness for a topper that has the least possible risk and the best chance for success. It also includes a link to a list of some of the better and more reliable online sources for toppers I’m aware of as well.
Phoenix