#2 The quality of LaLiga is much better compared to Ligue 1
This is an obvious issue. With all due respect, Ligue 1 does not rank at the top among the top 5 leagues in Europe. PSG have been dominating the title in recent years, no one even gets a sniff of it. Domestically, PSG is the ultimate dominator. When they move to the Champions League, however, they get an eye opener and haven't been able to make it past quarterfinals, even though the players don't lack talent.
Ronaldinho left PSG and created a legacy in Europe that was not seen from him at the club. He would never be remembered as a PSG player. Many people don't even know that Barcelona signed him from PSG.
The defenses in Ligue 1 are just too easy for players like Mbappe to dance around and beat. Even Malcom destroyed defenses in Ligue 1, that too, without the quality of players that Mbappe had around him and while playing for Bordeaux. You just don't know how good you are in Ligue 1. It is all a delusion.
On the contrary, LaLiga would be an eye-opener for Mbappe that it is not that easy to just accelerate and go past the whole defense. He would face quality defenders like Gerard Pique, Samuel Umtiti, Clement Lenglet, Diego Godin, Gimenez etc. Even the teams without world-class defenders are stubborn in the defense and are very intense in pressing like Valencia and Sevilla.
If Mbappe really wants to prove that he is a cracker irrespective of whom he plays against, he should try himself in Spain.