Lamine Yamal is still young and it is very difficult to predict what he will be like in the future. For now, he is playing well above his age and doing wonders. He gets into positions, scores goals, makes goals scored. It is very difficult for a football player at this age to do this because the players he plays are strong players who have completed their physical development. If PSG convinces him, I think they will fill Mbappe's void in the future.
We can't compare Kylian Mbappe to other players because during his peak as a teen, he represented himself at both club and international level of football. He does the impossible by winning the Russia 2018 world cup at the age of 18 years and youngest player, I'll paused here because there's a vast records surrounding the Frenchman. Let's look at Barcelona players, Lamine Yamal is prominent player for the team and have deliver the club when they needs him the most, he won't stop doing wonders because he's the most important young player currently. His personal vulnerability to injuries are slim unlike Pedri, Gavi and the rest, easily attached themselves to longterm injuries.
Kylian Mbappe is a great player. They last saw the final of the World Cup and gave the cup to Argentina with a dramatic ending. I think they had one of the best cup finals in history. Mbappe was one of the players who won that World Cup. He's coming off a great season right now. Most likely, he will continue to work wonders with Real Madrid at the end of next year. His style of play is great and I admire that.