Sleep EZ configuration help

I have had my mattress for just about a week! I went with side Talalay medium Dunlop extra firm base

I am 5ft 7 178 pounds very dense and muscular with wide hips and wide shoulders strict back sleeper only

I am noticing ankle, knee and shoulder pain where the mattress is “ pushing back” on me! and the areas that are making direct contact and causing “pressure” feel great and supportive!

Unfortunately I “split” the mattress on the bottom 2 layers but it’s one solid sheet of soft on top ( my fault didn’t notice I did that)

Could it be too soft on the top causing the outer extremities to feel more push back? Never had latex before and really like the support otherwise.

Almost wonder if I should have gotten the 10 or 13 inch model now tbh

Thanks and sorry for the rant