Battery drain very noticeable on SE 2020 (14.0.1), even in idle with everything turned off (Wi-Fi, Bluetooth, Cellular data) and all apps closed it drains 1% per hour, while on iOS 13 it would be 1% per 3 hours or more.
It also drains a lot during usage too, 1 minute of background time receiving a few notifications on Gmail and Slack, drained 5% in 1 hour, it's ridiculous.
None of this was happening with 13.6.1