Tacoma bouncing on interstate with oru designs camper

Hello all, I have a 2015 Tacoma access cab with 80k miles and I just attached an oru designs camper, which is like a project m from four wheel campers, where it attaches to the bed rails. This camper weighs about 400 pounds and my truck has been bouncing, bucking, whatever you want to call it on the interstate here in Utah. It's not the best highway and is primarily concrete. But I installed some icon rear shocks with an add a leaf as suggested by an overlanding store here, and it kept bouncing. After that another shop recommend that I replace the front stock shocks, so I put in some Bilstein 5100s. Now I feel like it's bouncing even worse. Has anyone had this problem, or has a solution or idea of what I could do to fix this?

 

Welcome to the forum.
Might seem like an odd question but what tires and pressures are you running with them?
Cheers.

 

Need some pictures, namely of bump stops and distance to axle, rear spring arch.

AAL are and band aid and can invert as well.

I suspect its sagging and the drive shaft is un happy along with suspension.

 

I have Pinza AT tires, they're 5 ply and I have tried tire pressures between 30-35 psi and 30 seems to make it better.

I have ordered the Icon RXT leaf pack that I will be installing this weekend as I believe the leaf pack can't handle it and it looks a little inverted towards the front when I looked at it the other day. I have also read that 2nd gens are notorious for having weak leaf springs so I am hoping this will be the fix. Will post pictures later.