A 5,000# trailer hitch does not give the Sorento a 5,000# tow rating.
The 2018 Kia Sorento with a factory installed tow package has a 5,000# tow rating. If your Sorento had a factory installed tow package, it would already have a tow hitch. That means that your Sorento may have a lower tow capacity (Class 3 hitch is only part of that package).
Check YOUR vehicle's Owner's Manual to figure out what YOUR vehicles capacity is. Also check to see if Kia recommends a WDH be used on the Sorento. Some uni-body vehicle manufacturers do not recommend using a WDH. On the other hand, I think that the Anderson Hitch would be safer on a uni-body vehicle because it does not use the solid spring bars like most WDHs. In the event of a rear collision, the chain-link WD system will collapse and not be driven into the body, like a spring bar WDH........ just my humble opinion.
The below website might help. Basically:
3,500 lbs. towing capacity with Front-Wheel Drive
5,000 lbs. towing capacity with All-Wheel Drive
Kia's All-Wheel-Drive includes a very sophisticated electronic braking and handling system that would be an important part of the stopping ability of the all-wheel-drive Kia. Your Kia's stopping ability is FAR more important then the vehicle's pulling ability.
I would think that the factory tow package may also include an auxiliary transmission cooler and possibly an engine oil cooler.
Don't rely on your Kia Dealership for towing info. I used to be a car dealership Service Manager (for 20-years). I can assure you that there is very little training in vehicle towing ability. You can likely get more accurate info on the internet using reputable sites (not forums like this).
https://www.executivekia.com/what-is...wing-capacity/