Apple has a Federal gov’t settlement offer - for $29 they will replacement the battery on your iPhone but that expires December 30th!
I know but I'm waiting because they'll probably turn me down unless it's at 80 or 81%. Either way my local Korean shop replaces them for the same price and he used a decent quality battery for my old 6 that I gave to my mom. She doesn't need the fastest phone but just one that works. It still has 100% and I did it back in February or so.