Even though Mbappe has stated that he will leave, but it seems that there is still no certainty about which team he will go to, even though indeed, so far Mbappe has always been linked with Real Madrid so maybe this will actually mean that Mbappe will play for Real Madrid next season. Also, based on one of the sources I got, what they said there was that Mbappe joining Real Madrid meant that Mbappe would also get a bigger salary than the salary Mbappe got at PSG. If that really happens, then of course it would be the right choice for Mbappe to leave and choose to play at Real Madrid. Because apart from getting a lot of money, Mbappe will also have a very big chance of getting lots of trophies during his career with Real Madrid.
PSG and Real Madrid are never respectable clubs, all the players who have come to Real Madrid have improved a lot in the future and their market value has increased a lot, on the other hand PSG has no such record.
Mbappé was at PSG and he was an iconic player of PSG and PSG depended on him a lot that's why every season this player's salary and bonus was increased so much that he stays at PSG but Mbappé won't actually get that chance at Real Madrid. But money is not everything in life, if he can take his qualifications to a good level, he can earn a lot of money in the future and take his skills to another level. Real Madrid we are waiting for that