We have a large teardrop trailer that we tow with a Subaru Outback H6 rated at 3,000 lbs and the key 'with brakes!
I have the largest transmission cooler that will fit and switched the transmission to synthetic oil and use a 60 40 mix of antifreeze which gets the boiling point up to about 260F and I have an Ultraguage that tells me the actual coolant temperature. The tear has an all aluminum frame and is about 1700 lbs loaded.
Last summer we traveled from near Toledo Ohio out to the west coast and back, and there were a number of times we had to switch off the AC to keep for over heating and drop to third gear in the passes. We camped at Tioga lake at 10,000 and just barely made it into camp steep grade with the foot to the floor in first gear, (altitude with a non turbocharged engine. Descending Tioga pass the next day about 4,000 feet and a sharp drop with trailer brakes the tow vehicle brakes were smoking.
The 01 H6 Subaru was about 225 hp at sea level and I went to lengths to keep it in one piece and happy. Can you get away with towing with a Kia, yes probably but you need to take extra care, switch to synthetic oils, get the transmission cooler and do NOT over load it.