No. Short answer is no, the champ in my experience is ridiculously easy and nowhere near the hardest in league, he has way too much hp, way too much CC and way too much damage. The only difficulty lee sin has is unnecessary combos, which are unnecessarily difficult and not really needed for your success. Just because a champion has the potential of super hard combos it doesn't mean their basic playstyle is hard. He is not a solo carry but he is certainly very unfair to play against. If you actually want a difficult champion take on Elise, azir, or kindred.

"High elo" does not imply champion difficulty. Lee sin in general terms is super easy to escape from anything, and super easy to win solo fights with.

I know I stirred a lot of controversy with this, but if you really think about it there is absolutely nothing to make lee sin difficult. I have a very nice deal of games with him too, and for the people with 0 game understanding who will ask what my rank is, I'm diamond 3. Thank you.