Hi Bouven,
If there is no sagging or soft spots in your mattress and the only issue is that it is too firm and you need additional pressure relief then a topper can be a good choice but if your mattress isn’t in good condition or has soft spots or sagging then a topper would likely only be a partial or temporary solution at best. There is more about choosing a topper in post #2 here and the topper guidelines it links to.
Some of the better options and possibilities I’m aware of in the Madison, WI area are listed in post #5 here.
Phoenix