iPhone 12 battery life deteriorated fast

Hi friends, I bought my iPhone12 in nov, 2020 and have been using coming to 8 months. I happened to checked on my battery life this morning and was utterly shocked to see that the battery life is at 92%. I’m not a heavy user and every night I switch off my phone when I go to bed. I don’t charge overnight either. I have an iPhone 11 which is my co. Work mobile. Had it since may 2020 for a year now and the battery life is still at 99%. Being a work mobile I use it heavily and I only switch off this phone occasionally at night. Due to my heavy usage, I frequently place this iphone 11 for charging in my car.

i’m aware that 92% is still within the standards of tolerance in apple technical specs. But I cannot understand how can it deteriorate so fast in just 8 months? How is it going to last for another year or so?

may I ask if any iPhone 12 users encounter similar condition on your battery life? May I seek the advise from any iPhone experts here in the community? Hope to hear from someone soon. Thanks.