Messi if moves to Paris he should agree salary... then spring on them that he agrees to sign only if the Mbappe money goes to Barca or at least a 100m sweetner.
Gets his move, Barca helped financially and the world is a better place.
How does it work exactly ? Messi will be a free agent, there will be not even a cent paid to Bar?a. Remember Messi wanted to leave for free this summer too by using his clause.
What will happen is Messi will say :"Gimme the 100 millions as sweetener for my backpocket".
Also, the best option for his legacy is simply staying at Bar?a. He is a legend, he will be revered for staying there and maybe be a 1 club man if he doesn't go to USA next.
The best option for the challenge is Manchester City. He would also join Guardiola who he respects and admires.
PSG doesn't offer him much except for the Neymar amigo reunion. Performance non aknowledged in the league and criticized in CL anyway. Just look at Neymar, did the PSG move help his legacy ? He can make the best games of his life at PSG and it won't matter. When the team gets eliminated when he is injured, he is mocked. When they go to the finals and lose, he is still mocked. There is no winning going to PSG for your legacy unless you win everything.