Hi sheshechic,
A thicker topper can work to remove the obvious “feel” of a minor dip (by the time the compressive forces reach the polyfoam they have spread to a larger surface area which can even out the soft spot to varying degrees) and if you are OK over your longer term sleeping experience as well for alignment then you would have “hit” the best possible balance between pressure relief and alignment and this would be great news :). The topper will also slow down further softening of the polyfoam underneath it.
There are a few “sheet” options as well listed in post #26 here including one where the pocket depth can be custom ordered.
That’s also great news … with pillows being such a personal item and with so many personal preferences involved that are unique to each person … finding the “perfect pillow” is a rare occurrence indeed!
Phoenix