With Haaland signing with Man City, I think they are definitely favs to win the Premier League again next season. You can't really get a better striker than him at the moment(maybe Harry Kane?). Striker was the only role that Man City were really lacking in. Even though Pep's style of play doesn't really require an out and out striker, it will he handy to have one in clutch situations where they could whip a high cross in, instead of trying to put in low through balls.
Their success in recruiting Haaland to join Manchester City is the best transfer for now in my opinion. This name (Haaland) has always been discussed lately following the brilliant performances he showed with Borussia Dortmund. Yes, Manchester City are the lucky team to get this talented young player. Retaining the title next season is very possible.