I have had the same issues. Just today battery went from 70% down to 7% in 2 hours. All since downloading IOS 14. Currently on 14.3 but still same issue. I am also having big time issues connecting to wifi. Have not been able to connect to any wifi since the IOS 14.3 update. I have tried just about everything mentioned.

Apple. You need to fix this issue. This is ridiculous. It’s obviously an issue with IOS 14.3.

So basically turn everything off! Sounds like a good fix! I am having several other issues. Wi-fi dropping at home. Cannot connect to any wo-fi outside of home. Blue tooth connection is terrible now. So much static it’s unbearable. And of course the draining of 100% of battery in about 2 hours. All since IOS 14.3.