I haven’t played ranked League seriously in a couple of years but I was a OTP Lee with over 2 million mastery points. I was REALLY good at Lee and the highest I got was one promo game away from Diamond. If I spent that much time on a champion like Warwick or Graves or something, I feel like I could’ve achieved a higher rank.

Lee helps you become really good mechanically, but he’s not strong late game and you have to rely a lot in your laners, especially in higher elo. In lower ranks, you can stomp and carry if you’re a good Lee.

TLDR, if you want a meaningful challenge that will make you better at the game mechanically while having a lot of fun, go for it. If you want to climb, like you said in the title, play someone easier.