Hi FAUguy,
Just for the sake of clarity … there is really no such thing as “up pressure” (from a mattress) or “down pressure” for that matter either (from the weight of your body) because when you are lying still on a mattress the pressure you feel has no “direction” and the opposing forces are balanced between the compression forces from your body and the resistance from the mattress (see the last part of post #11 here about “pushback”). Even materials that have little to no resilience at all (resilience is the "up pressure or “springiness” of a material) such as memory foam become progressively firmer and more resistive as you sink into them more deeply.
Resilience does have an effect on the “feel” of a mattress and on the ease of movement when you change position or get out of the mattress and can help with some of the “other activities” that happen on a mattress (see post #2 here) but it doesn’t affect the pressure relief of a mattress and isn’t a factor in the firmness of a material.
You still are in the early stages of your break in and adjustment period you have some good options available to you if your mattress ends up being too firm although of course you can’t change the resilience of a material and this is part of why some people prefer some types of material over others (although a layer of a less resilient material on top of your mattress can certainly change the surface feel and resilience of a mattress)
Phoenix