I am noticing a battery drain lately as well, but I’m on iOS 14.4.2, so I am no longer sure if it’s exclusive for iOS 14.7.1. Last night I went to bed with 57% and woke up 5 hours later with just 49%... went to bed again after peeing, and when I woke up again it was on 37%... which dropped quickly to 30% after checking the news on the morning for 20 minutes or so.Hmmm... And I'd thought maybe I'd been imagining it. Guess not. It's not excessive, but it's noticeable.
Sure, it could be my batterie’s age, my iPhone 8 is almost 3 years old, and it is at 83% of battery health. But this started to happen not too long ago.