Paul Horowitz writing for OSXDaily.com:
Some iPhone and iPad users have reported that battery life is suffering after updating to iOS 14.6 on their device.
My normal practice is to wait a few days before installing OS updates. I want to see if the update is presenting any new issues. I was alerted to a possible battery issue with iOS 14.6 in a May 26th blog post by Lee Peterson. Therefore, I did a some research and found that several folks were having problems with rapid battery drain. I’m going to hold off installing 14.6 and wait for a fix.
As a side note Apple has stopped signing iOS 14.5.1, blocking downgrades from iOS 14.6 according to 9to5Mac, so this is no longer a possible workaround.