your build is probably to high above the air intake causing a harsh throat hit. Just push it down so it's about 1 mm above. Also would recommend going for a 2 ohm build or less. 1.5-2 ohms works really well the Kayfun.
Far as heating issues go, most likely it's because of the amount of wick you have. The more wick and juice in the chamber the more heat is retained causing the entire atomizer to over heat. This could be related to your high ohm build also.
The kayfun can be built many ways and most work quite well. I have tried most of them and my best build for the Kayfun is a dual series vertical mounted micro coil with external wick. I used to use cotton but now using hemp fiber, which I prefer for external wicking.
Try wrapping you build again with half the amount of wraps. Also check out the micro coil build thread for an excellent way of becoming proficient in building. I use micro coils in all my rba's in one form or another. Just so much easier and consistent for me. Also consider picking up some tools of the trade as you go along. A butane torch is a great tool to have for torching wire, setting coils, and oxidizing SS mesh. Also, if you don't already have one, an atomizer ohm meter is great to have. More accurate than the ones on the mods, and provides a great platform for your rba while mounting the build and wicking it. Needle nose pliers and tweezers are good to have also. I also have a selection of blunt nose syringe needles for wrapping micro coils, great for changing up the diameter of the build and holding coil while mounting it.
Good luck, have fun, building is a constant source of joy and frustration. lmao.
