If you are over the age of 20, you need to forget about Messi because you ain't ever in your lifetime gonna see a better player than that. Unless of course they invent a pill that increases longevity of life.
Lamine should be compared to similar players in his position. Left footed right wingers. Salah and Saka immediately come to mind.
For me, he is better than Saka right now. And Salah only really has finishing better than him. I'd give it 3 years max before he brushes up on his finishing and becomes the best right winger in the world.
Then, Mbappe is the target for best in the world and Ballon D'ors etc. Here it becomes more difficult to judge. I personally think he can get there but it will be largely dependent on how much he improves his finishing and him becoming a regular 30 goal a season man.