I think an app that schedules tasks around when you’re most energized could really boost productivity. But I get the concerns about tracking data. It might make sense to lean into some more passive methods for gathering info. Like, maybe use the sensors on our phones to keep tabs on activity, sleep, and location to figure out when we’re hitting our peaks.
Also, it could be cool to add some gamification—like giving users points for checking in on their energy levels or for knocking out tasks when they’re firing on all cylinders. That could help keep people engaged with the app and make it more useful.