TC owners frequently use hitch extensions, sometimes as long as 48” so they can tow a boat, snowmobile, or even a large enclosed cargo trailer.
What usually gets left out of the discussions about the physics of using a hitch extension is what’s on the truck end of the lever. There will be a huge difference in the handling characteristics of a pickup using a hitch extension with an empty bed and one that has 3-5K lbs of weight in the bed.
I know that’s extreme compared to what you are doing, but the physical effects are linear. If you extend your hitch a few inches to provide clearance for your tailgate and notice a change in the handling, try putting some of your heaviest gear in the pickup bed to change the weight on each end of the lever.
:):)