It is possible if Joshua Kimmich considers to move to EPL teams but I am not sure he wants to join Man United. Man United is a very unstable team, Joshua Kimmich will risk his career if he decides to join Man United. I think he will prefer to join Man City, Liverpool, or Arsenal that perform better than Man United in every season.
I guess that Joshua Kimmich will for sure not leave Bayern Munich and that his contract there will be extended in some way.
If he really join another Team (what i dont thin) it will be maybe only 2 or 3 teams maybe , Manchester City or Barcelona have the best chances.
But in my opinion he will stay in Munich and he will end his career there when the time has come for it.