Hi rjar,
Thanks for the update and that’s good news because it’s certainly easier to fine tune a mattress that is a little too firm and needs some additional pressure relief with a topper than it is to change a mattress that is too soft which usually requires the removal and replacement of some of the foam layers or a replacement of the mattress itself.
Before you consider a topper I would make sure you have slept on your mattress for a while because of the adjustment and break in period that are part of any new mattress purchase and there are also other factors that can affect the feel and softness of your mattress (see post #2 here).
If you do decide that a topper would be helpful then post #2 here and the posts it links to have some information and guidelines that use your assessment of your sleeping experience to help you make the best possible topper choice.
Phoenix