@Diamond+ players: How many of you learned the game by playing simple champs?

I keep hearing the same advice to "just play Annie" from a lot of people whenever the topic of trying to improve comes up. Started wondering how common it is that people actually do this and reach a higher rank as a result. If you're diamond or above, what did you play while you were learning the game and would you pick something else if you had to do it all over again?