Stick to the 75% rule and you will be fine.
A 4100 lb trailer will 5000-5500 in real life.
Your vehicle is rated for 6200 lb. 75% of 6200 is 4600.
While you squeeze under IF EMPTY, you will wear out your JGC quickly pulling so much.
The 14 JGC unless it has lots of extras, like aux cooling, and other "trailer package" add ons, was not made to pull a 21' trailer.
If nothing else, make sure you have working trailer brakes, and a good weight distributing hitch, properly installed, based on the tongue weight rating of you vehicle.
2012 FF 214WSD and Equalizer WDH
2019 GMC Sierra SLT, Crew Cab, 4x4