You missed the part where my truck weight of 4,800 pounds includes me, the dogs, and gas. Aluminum engine and aluminum body does amazing things in weight reduction. How about this, truck GVWR is 6900 - (ME, MY Dogs, A full tank of gas and the truck weighs 4,800 pounds. That is total weight). Leaves me 2,100 pounds for a hitch (200), the wife(?), and pin(1,600). Plenty of capacity. I don't have a truck box, tools, tonneau cover in the truck. Why would you put them in the truck when you can put them in the 5er? We are set up differently. I don't have excess weight in the bed of my truck like you do.
As for the load, I can tow 10,600 on the ball. No problem pulling an 8,000 trailer, plus a 2,300 boat. Total is 10,300. In Illinois, I must have a 5th wheel to be legal triple towing. Even then, 4,800 + 8,000, + 2,300 = 15,100 + the wife and hitch. Again, under capacity. This all assumes one thing, the trailer is maxed out at 8,000 pounds. Every 100 pounds shaved off the 8K, is 20 pounds shaved off the pin and 100 of GCWR. Not sure how you camp, but I have been tent camping for over 4 decades. I barely carry 200 pounds of gear for a weekend, food and beer included. When I backpack, I carry about 35 pounds for a week, total pack weight, including food. The only difference between car camping and the 5er is I will drop the 30 pound tent and pick up 5,500 pound camper. Nothing else changes. I find it hard to believe you need 2,500 pounds of camping gear. Realistically, if the 5er is 5,500 off the lot I will add about 300 pounds of gear and food for a week long trip. 5,800 is well below 8,000.
Let's assume 500 pounds of gear. At 6,000 pounds for the 5er, I drop 400 pounds on the pin. 1,200 pound pin weight is something most modern 1/2tons can handle. Which is what the OP is after. I'm pushing the limits. My trips will be limited to 8hours or less for camping and fishing. I know I'm pushing the limits and I'm Okay with it. I'm also not going to buy a 24' or longer 5er. I need a 20' 5er and that will drop my total weight even more.