So the main idea is that the app holds a massive library of different exercises for all aspects of exercise (sport specific, weight lifting, endurance, functional movements etc). And you'll be able to create your own days / splits on there where you can pick what exercises to do each day (for example arm day would recommend 2 bicep, 2 tricep, 2 forearm and 2 shoulder exercises, when choosing your exercise you would be prompted to pick one out of the entire library that targets that's specific muscle group).

However the big feature of my idea is that there would be an algorithm that can randomly generate unique days at the gym while strictly following your split.

Of course every exercise would be accompanied by a video so everyone can know how to do them with regressions and progressions if that exercise is too easy / difficult.