Diamond/hybrid false 9. So Messi can play the Hook. Neymar plays as the SS who drifts left and if he stays Mbrappe as the ST who drifts right. Which then allows Messi to take the Central role as 10/false 9
Defensively 3412 might be better but if you have Hakimi and Ramos on the right side. That's the side you attack down. Hakimi will do his best Kyle Walker impression and Ramos is Ramos either get pulled out of position or give away freekicks and get bookings.
Also if the rumours are true PSG want to get rid of about 10 players. Most of them will be the midfield workers and back up defenders
Ramos Marquinhos and Kimpembe staying injury free for the whole season