Having a hitch stabilizer as you have done is a big help.
We have a DK2 hitch carrier. I also added a stabilizer.
We carry two Harbor Freight 2000W Predator generators back there, strapped down and covered with a heavy duty BBQ grill cover and bungie corded down.
I also added 1.5" aluminum tubing that slides right up into the welded hitch frame, then bolted to the carrier. This also help with any sway.
The carrier has an extended tongue so that reduces the weight carrying capacity a little.
Altogether we have 180lbs on the hitch (carrier + 2 generators, each weighs 60lbs).