That's kind of what I'm thinking too.
a number of half tons are built with very high gears ratio (numerically lower numbers) to maximize fuel economy, and that makes for a bad experience towing.
Speaking for GM's 6 speed transmission, not true.
My '11 GMC crew cab had the 3.42/6 speed combo. Best towing experience I've had with my trailer, and I've towed it with an 04 Dodge Ram, 3.92/5 speed 05 Suburban 3.42 4 speed, and 07 Suburban 3.73 5 speed. Only towed one time with my '14 Chevy with the 3.42/6 speed and again it pulled great.
If the OP has the 5.3 with the 3.42/6 speed combo, towing a rig similar in specs to my 27' 5500lb KZ will be a very good match for his truck.