I had the exact same issue. Currie 4” springs and new bilstein 5100s for a 4” lift. The rear shocks would bottom out all the time especially towards the end of the day. (Shocks would overheat?)
I switched to 4.5” RE springs in the rear hoping the stiffer spring would help.. nope, it didn’t.
So I got a set of bilstein 5160s for the rear only (essentialy a 5100 with a resi?). It solved my issue immediately. No more bottoming out.
I have a tire carrier, 35” MT mud terrain, and HIgh lift jack mounted on the rear.
View attachment 124804