Guardiola will end up leaving Manchester City by the end of his contract or a couple of years later or if he sees that managing a national team might be interesting for him, if the offer was interesting eventually
It is very possible that the coach of Manchester city will like to take up a new challenge in a new league with a new club, trying to lead them to win the champions League the local League as he has done in Barcelona and Manchester city. Since he became the coach of Manchester city, he has raised the status of the club from the regular club to a world-class club and many clubs will be privileged to have Guardiola as their coach. I do not see him as someone who will like to be the coach to a national team.
I don't believe Guardiola would want to change teams. Everything is fine with the Manchester City team at the moment. He is the boss of this team. The players respect him a lot. I'm sure we'll see a few more great seasons. If he goes to another team one day, it could be Barcelona.