POOR Battery Health
I purchased iPhone 11 Pro, after 8,9 months of use my phone was suddenly dead. I claimed and apple replaced my phone. Now after six months my battery health has drastically been reduced to 81% . I use original charger and charge with care. Why this has happened to the battery, is it a problem with replacement phones or there is an other issue? please also guide me what should I do now?
iPhone 11 Pro, iOS 14