Well, I believe the same happened with Cristiano Ronaldo, I believe that the 2022 World Cup was the last for both Messi and Cristiano Ronaldo, I have no doubt that in the 2026 World Cup they will be able to be physically prepared and will be able to both play for their teams, but I have no doubt that the performance of Messi and Cristiano Ronaldo will decrease...
With the performance that Argentina presented in the first games of the 2022 world cup, I would never have imagined that they could win that cup, I would believe that Brazil could have reached the finals, but unfortunately Brazil made unacceptable mistakes against Croatia's game and lost that extremely important match
Can't be sure about the situation of Messi and Cristiano Ronaldo in 2026, we know both players are still superstars in their teams, Messi is still playing for a top European team while Ronaldo decided to continue his career in an Asian team with more money but can't be a reason to say Ronaldo should think about stop playing for his national team soon, also since Messi was one of the best players in 2022 world cup, he still has a high chance to play for Argentina in 2026.