Wow, I know that people report that after a few days things might return to normal, but as of now iOS 13 has absolutely decimated my battery life on my relatively new SE. My battery health is still at 97% and supporting peak performance, but I've lost well over 4 hours total battery life. Used to to pull it off the charger in the morning and at bed time still had easily 20%+ (I almost never saw the prompt to enter Low Power Mode). Now I'm running completely out of juice at around 6pm and seeing a bunch of other wonky behavior such as shutting down and demanding that I plug it in - after which it was immediately at 25% power and charged to 50% in about 10 minutes. Not cool Apple.