Mbappe is 24 years old but has only 222 goals, not too much more than Haaland.
And reaching what Messi and Ronaldo did is not easy, it doesn't just require to be a top player no matter how old you are, it is obvious that you would need to be scoring 50+ goals even when you are 35 years old as well, and you have to be not get any big injuries for the next 15 years and keep being consistently this good. I am sorry but that doesn't feel possible to me.
I think its really hard for both players to perform at such a good level for such a long time. To score 50+ goals per year is really hard and both players werent close yet but with them playing in the best teams in the world i think they will reach im upcoming year 50 or more goals per season