I also have a Demco Recon hitch in my truck and I've had no issues with it. Sometimes, the road will be so rough, or I'll hit an expansion joint on a bridge where the trailer will actually left and slam down on the hitch, but that is very rare. I have no chunking either, and no banging when taking off or stopping. My previous travel trailer did a lot of "banging" because my receiver hitch had a lot of slop in it, allowing slight movement forward and back, causing banging. But not with the Recon.
However, on many, many occasions, with my fifth wheel, even though the roads may seem perfectly smooth, when arriving at our destination, things are in a disarray in the camper. Drawers may even pop open, things fall, and things get shuffled around in the cabinets.
Over time, we've learned how to button things down a bit tighter. When things move around in the camper, it's not the trucks fault. It's the trailer simply bouncing up and down, sometimes violently.... an it's never noticed inside the truck.
If things are moving around for you in the camper, then you need to secure them better. It's just that simple. Another thing, if you are driving like you would normally when not towing, you are driving too fast. Most trailer tires are rated at 65 mph. You should never tow faster than what your tires are rated for. Even if the speed limit is 80, you should never go more than 65 if that's the tire rating. Also, faster driving causes more aggressive g-forces bouncing up and down on the camper.
I have a feeling, all you need to do to correct all your problems is to slow down when towing. It WILL make a huge difference in how much things get beat-up inside the camper.
2019 Montana High Country 375FL Fifth Wheel
2014 Chevy Duramax HD 6.6 - 3500 Diesel Dully Long bed Crew Cab