Your main focus here is to get some weight on the front axle of your truck to get stability.

Without seeing a side-on shot of what it all looks like loaded up, I can offer this:

If it was me, on your next outing, back the car in. Getting the engine weight further back should off-set everything you have in the cabinets beating on the truck.

Balance your trailer weight. Scaling is the proper way, but start with the wheelie bars at the cabinets, get out, have a look, and then keep rolling the car a few inches toward the back door at a time until everything sets right. A 3/4 ton should only squat a few inches.

Go for a drive and see what the difference is. You'll know when it's right when the front-end feels glued to the road and it pulls easier.

Biggest thing to keep in mind is that a tow vehicle is meant to pull a trailer, not carry it. Move weight to the trailer axles, not the hitch.

Those torsion hitches are a last-resort, band-aid fix for a poorly designed/balanced trailer.