Every battery will degrades eventually. Just enjoy the fast charging normally as nowdays all charger are efficient & smart will auto disconnect but be sure use top notch brand such as your aukey.

Once you start fast charging you will not go back to cute little 5watts. Same as wireless charging since I started to use wireless charging its very convenient and my battery ready to go anytime unless need extra juice of power ASAP.

Just be sure your ip not overly heating up such as your case are too bulky/less heat dissipation.