The first thing you have to look at always is the loaded weight of what you are towing and the tow capacity of the tow vehicle. The dry weight of your boat is as far as I can tell close to 3000 lbs. Add 1000 lbs for the trailer. Then add for equipment you’ll have in the boat and a full tank of gas (about 6 lbs per gallon). Then you have to look at GVWR (gross vehicle weight rating) of your tow vehicle. This includes weight of vehicle, passengers, cargo, fuel in tank, and the tongue weight of the boat/trailer. I have an idea you will be close to or exceeding that weight. (exceeding that is dangerous)
Even if you are within (barely) these weight ratings your towing experience may be unpleasant, not relaxing, not fun. May even be hazardous and dangerous.
In addition the closer you are to the max weight ratings the more stress and wear you put on the drive train, suspension and brakes when towing. For safety sake and a number of other reasons you need to look at tow vehicles that are more substantial with higher weight ratings than what you’re looking at. You dont need a Ford F350 diesel but you should be looking at vehicles that have a tow rating of over 6000 lbs.
Lastly I hope your boat trailer has brakes. Because trying to stop that load with a KIA and a trailer without brakes is going to be hazardous to you, your passengers and others on the highway.
Get a vehicle with a tow capacity exceed 6000 lbs. Because you can tow something doesn’t mean you should.