As others have said, replacing battery is fairly straightforward for 6s, I did it a couple times on mine until replacing a few months back. Look for the higher

As others have said, replacing battery is fairly straightforward for 6s, I did it a couple times on mine until replacing a few months back. Look for the higher capacity batteries, I had luck with Amazon. Will take you probably 30 mins to switch out. Alternatively - I just upgraded to an iPhone SE which seems like essentially the same phone as 6s but a little faster/smoother. Fits my minimalist needs which sound similar to yours. Dealing with the Android crapware sounds a lot less fun to me.