What is killing my battery?
No, there's nothing in that list which is "killing" your battery. The battery degrades during normal use - that's not preventable and to be expected. 

Batteries are not all alike. Some degrade faster than others - you cannot say that the battery capacity shrinks x.xx% per year in general and expect that exact number on every phone.

Apple states that the battery is designed to retain up to 80% of its original capacity at 500 complete charge cycles under normal conditions. You're still well above 80%.

Having 90% capacity after 222 charge cycles seems to be quite alright - i.e. it is likely that you’ll be at approx. 80% percent after 500 charge cycles.