Barcelona are in huge financial trouble plus they are in danger of being disqualified for their financial dealings with refereeing officials. There is practically no chance that Messi will return to La Liga. And it’s hard for me to imagine what serious club in Europe needs him now, most likely he will go to the MLS, but maybe to the sheikhs (although this option seems less likely to me since it is less prestigious).
Last statement from Lionel Messi he wants keep stay with Europe team for next season if not reach agreement deal with PSG, but seems disappointed because Messi is the icon how to make Ligue 1 more interested. I don't think if Leo Messi leave PSG and how Ligue 1 popularity for next season.
Return to Barcelona seems not possibility because this club have problem with financial and they can't pay huge salary for Messi, but Saudi Pro League teams want to pay more interested salary for him and Primer League team not any confirmation yet want to signing Messi because Manchester City as team linked with Messi last season not any official announcement yet interested with Messi.