iOS 13 on the iPhone 6S and SE: New software runs fine on a phone that's still fast | Ars Technica
Battery drain & iOS 13.3 | MacRumors Forums
Help] WiFi idle energy battery drain. Woke up and phone was at 50% from 100%. I've had battery drain issues since updating to iOS 13.3 from 12.4 : r/jailbreak
iOS 13.3 battery life tests (Video) - Geeky Gadgets