It's all about vehicle to trailer matching, and good setup.
Once in my 2 door Tahoe I was towing 2 jet skis. No problems there but on the way back empty gas cans up front, no tongue weight and it almost wagged me off the road. I had to pull over on the freeway and load river rocks in the front storage box to make it home. That was a 4x4 Tahoe with a dinky little trailer.
Then a 99 Tahoe with 20" wheels and rancho shocks towing my current 27ft trailer. With proper setup it was fine but I could feel the big rigs for sure since the TT was longer, taller, and weighed more than the truck. It didn't have a lot of sway but I could feel it pushing me around.
Now towing with the truck that the original owner bought with the trailer brand new....he was a big rig trucker (sadly he died 3 days ago of cancer). He went overkill with the F350 dually diesel. I have NEVER had sway. Total confidence when driving by trucks or even doing 90 in mexico on rough roads. It's a one hand on the wheel experience and makes towing way less stressful. In this case it's lots of truck, good setup and TT with shocks and load E tires.