Same problem on my iPhone 6s and 14.2.
While in standby mode the phone is a bit warmer than usual but the battery drain rate seems linear and just a bit more than with IOS 13.
When using the phone (using Safari) it gets warm and battery level drops very quickly, but in a weird way, in large chunks, like from 95% to 80% then it stays at 80% and suddenly drop to 65%. After an hour or so it drops to 20-25% After a reboot the remaining percentage may rise but suddenly drop again?! Please Apple fix this we need phones we can trust!