It it normal to have 89% battery health . I bought the iPhone XS on Launch in 09/18
I am not a heavy user and charge before it hits 20% to full..
what’s you percentage like?
Ideal vs. actually harmful are somewhat different things. While not charing to 100% can help extend battery life to some degree, it doesn't mean that charing to 100% would actually be noticeably harming it.Charging to 100% is your reason why battery is dying so fast. Max charging to 80% is ideal. Ios 13 will have a feature when it will keep the battery at 80% until the phone determines, based on your charging pattern, to charge to 100% just prior to you being active on the phone. If you keep battery between 40-80%, you will extend life significantly. My X after two years is still at 94% and I'm a heavy user. Don't let it drop below 20% either, both extremes are very bad for lithium batteries.