It is difficult for other players to replace De Bruyne role in the Man City midfield, but Pep Guardiola definitely has a strategy to maximize other lines in order to win the match against Sevilla. This means that Pep still has alternative players who can fill the void. Sevilla has just received defeat in their opening match in La Liga this season, my prediction is that Man City will play as usual by dominating the game.
Seeing the conditions of the two clubs, I think the final score in the match will not be too much, maybe 2-1 for Man City victory.
I don't think losing De Bruyne has had much of an effect on Manchester City's game as a whole. Pep Guardiola, of course, has prepared several other schemes that keep his team stable. Mateo Kovacic is the right alternative to fill that void and he is also a player who is quite experienced so I think Kovacic will be able to give maximum role in midfield. City will certainly win against Sevilla in the Super Cup Final, I have absolutely no doubts about the capacity of Manchester City under Pep Guardiola.
Oyes, it does. De Bruyne and Rodri are the main defensive squad of Manchester City, they are very convertible in any matches they have and if you observe carefully, Kovqcic is not durable as him. Haaland hardly makes goal in when De Bruyne isn't playing, he don't have goals because he is just another tapper, it's absurd when the compare him with like of Messi and Ronaldo because of his contributions in just last season. Manchester City are even finding it hard to finish off Sevilla, they have everything but it seems Sevilla is just proven stubborn to defeat because even by ball domination, Manchester City is far ahead but Sevilla defensive line is like a concrete that is proven to be a blockage that are not giving up, perhaps in the next 5 minutes, they will get tired and Manchester City will win but if the other way happens, then you will understand the absence of De Bruyne.