Suspension upgrade recomendations for 2024 TRD 6 ft and camper topper

Hi
I am new to the forums.
I just put a Harker EXO camper topper on my 2024 6 ft TRD Sport. Before installation I added Coil Sumo Springs front and rear, but after adding the weight of the topper (~350 lbs) and knowing I will add more weight to the bed of the truck for a simple build out, it is seems I need to do some more to prevent the truck from squatting. With the topper alone the rear of the truck is sitting about 1 - 1 1/2 inch lower now.

I live in Moab, UT and will primarily use this around southwest UT and CO. I am not planning on doing any overloading and the majority of the miles I will put on this truck will be highway, but I like the the idea of being able to access campsites down rough roads and two tracks. I have never owned a truck before and never made any after market modifications so I am looking for recommendations from others. I assume most people on here know this vehicle is coil front and rear.

I contacted one suspension shop in a nearby town and they recomended just replacing the rear coils with something rated for an extra 800 lbs. Any advice is appreciated. Thanks