> It's ludicrous to me that the default behavior is plugging in your phone to a 30W ludicrously fast charger when you go to bed in the evening, where it then climbs to 100% charge and holds there while you sleep.

Apple already does something similar. It's not configurable beyond on/off but optimized battery charging on MBP, iPhone, and iWatch learns when you're normally awake and holds charging at ~80% overnight until a bit before your normal wakeup time. On MBP it holds at 80% most of the time during the day too if it learns you're rarely running on battery.