In my opinion the best champs to play when starting out is Annie or Garen, because their kits are very simple and easy to learn and once you learn the champion you can focus on macro, which is like game sense and game knowledge. So imo pick the easiest champ to learn game sense which you can take with any champ you wanna learn later. For example, even if you can't play a champ like a mechanical god, you can still play the game at a higher level because of your knowledge.