Barcelona have been looking for Messi a lot on the field this year. When big stars fall, they create big gaps. They couldn't make up for Messi's absence. If they don't create a big star, they will lose the league to Real Madrid again. Real Madrid have the advantage of dominating the league more than ever. They seize this opportunity well. The Spanish league will be similar to the German league.
It would be great to see Messi back at Barcelona. At least, I think a lot of people want that. The only question is whether this is contractually permitted. He left Barcelona, so in principle the counter is back to 0 for salary. Even if he would give up a little salary, that would still not be a problem. He will mainly want to win the CL, with PSG you have great opportunities for that. More than at Barcelona at the moment. Mbappe and Messi is a dream vanguard.