With Messi moving to Miami , I do have confidence that he will be playing at the next WC , especially that he will know all the pitches by then and having extra info even if the age won't forgive Messi but I would like to see him playing one more WC. Now , can Argentina win it again ?
Since Messi has not made any statement regarding his retirement so far we can initially assume that Messi may play one more World Cup but based on age and fitness he may retire from national level play after this season's Copa America. Because Messi has nothing to achieve at the moment, he won the World Cup last time. He might want everyone to say that Messi won the last World Cup of his life. Because there is no guarantee that he will win the 2026 World Cup.
I doubt it because believe it or not , England looks the strongest team on the planet right now , because they do have a lot of young talented players with massive experience in both WC , EC but also UCL and Premier League.

England were one of the favorites for the 2022 World Cup but ended their World Cup mission by losing to France in the knockout stages. Some of England's young footballers have been performing brilliantly in the Premier League and UCL recently and their skills have improved significantly compared to the 2022 World Cup.