While I am one of Messi's biggest fans in South American team, I believe the current team will need luck to win the world cup. The last time a South American team won the FIFA World Cup was Brazil. As a result, Argentina's chances are stacked against them. It doesn't matter what, European countries always dominate. Yes, it would be incredible to see Messi or Ronaldo lift the FIFA World Cup trophy in 2022.
I doubt Portugal will reach the final, although I would like to see it. Portugal has the players to get there, it remains to be seen if they will be focused enough for that.
But it would be very nice to see an Argentina vs Portugal final, because they are two teams that have never played against each other.
I wouldn't underestimate them. They are much more flexible and versatile than they used to be in the past. The offense is pretty strong in my opinion. If they are all available and fit I don't see a reason why they shouldn't be able to compete for the top 5 as well. I think when it comes to the semifinals and final, it is rarely the case that one team totally dominates the game. It is the little things that then decide it. On a good day we all know that Ronaldo can still score some crazy goals. Could become his tournament so to say.
It is very difficult to make predictions about the World Cup final. Ronaldo is Portugal's main striker, so we think the team is very strong. But Portugal as a team is not stable. Their defense is weak. Moreover France, Germany, Brazil and Argentina are very strong teams. And so before the start of the World Cup, it is not possible to predict which team will be the champions this time
Let me take a second and name a few: we have Ronaldo, Fernandes, Felix, Silva, Jota, Leao, and several other well established players in the top European leagues. I don't really see why Portugal shouldn't have a chance at all. It is not even all about Ronaldo anymore. That team can beat any team on a good day, but as you said they aren't the most stable team right now so they can also concede a couple of goals within a single game.
As I said before it really boils down to the form the teams will have at the World Cup, whether anyone gets a covid infection and can't play and so on and so forth. On paper right now I would say that Portugal might not be a favorite, but would you say that they are easy to beat?