The money they've offered Messi can convince him to leave Inter Miami for SPL but he doesn't want to play in a league which Cristiano Ronaldo's the main player. Messi's the main player in MLS & Cristiano's the main player in SPL he doesn't want it to change.
If Messi's going to join SPL he's going to get a mega contract. Cristiano's new contract with Al Nassr's given him power & wealth so if Al Ahli want Messi they'll have to offer Messi a mega contract. His family likes Miami it's home for his wife & kids so Messi's going to change their lives if he's going to SPL.
I believe that teams in the Saudi Arabian League will likely still struggle to sign Messi, even with substantial contract offers. As we know, Messi was offered a substantial contract by a Saudi Arabian League team in the previous transfer window, but he turned it down. So, given this, I don't think Messi is uninterested in the large sums of money offered by Saudi Arabian League teams. However, Messi likely chose not to join those Saudi Arabian teams because his family wouldn't allow it. As we know, the lifestyle in Saudi Arabia is very different from that in Europe or America. Therefore, if Messi played in the Saudi Arabian League, his family and perhaps himself would have difficulty adapting. Therefore, I believe it will still be difficult for teams in the Saudi League to sign Messi, even if the contract offers are very large.