In order to want to sign Messi again, Barcelona are willing to lose 11% of broadcasting rights because they will sign a contract involving La Liga and CVC Capital Partners. I don't know if it's the best chance for Messi to wear the Barcelona jersey again, but yes I think he still really wants to do it.
Messi is worth more than any broadcasting rights but the PSG and Messi deal is a done deal they are expecting him to sign today. If you are a barcelona fan I would not get your hopes up about signing messi again.
This is the type of thinking that cost Barcelona financial trouble. No player, not Messi now, not Messi at his best worths getting in debt for over a decade, that is just not acceptable and that should not be done at all.
I understand that he could be the best player in the entire world, he certainly was the best player in history of the sport, and he is still top 5 at worst case right now at this age, but still if you give up over a decade worth of income then how can you ever be good when Messi leaves? Eventually this dude will retire, and sooner than a decade for sure, he ain't playing until 45, which means you are giving up income for a period where he won't even play.
There is no logic in keeping Messi, let him leave and you can rebuild and eventually Barcelona will be good again, everyone with expensive salary will leave eventually, and they can rebuild the whole team.