Manchester City's performances last season were somewhat erratic as De Bruyne and Haaland missed several matches due to injury. And these two players are the most important players in City's squad. This is why we saw Manchester City's somewhat erratic performances earlier in the season. But Guardiola was able to keep the team stable. Manchester City looks to be stronger next season.
Arsenal need a stronger squad if they want to win the title. Arsenal need a suitable replacement, especially after a player is injured. If not, the Arsenal team will not be able to survive in the title fight with Manchester City. However as a layman I expect the Premier League to be more competitive next season.
De Bruyne missed a lot of games and entered gradually, but Guardiola does not like when the team's performance can depend on one player, so he tried to do everything possible to ensure that his absence was not so noticeable, although it definitely affected the game in the center. Regarding Haaland's absence, I can say that Foden was able to become a very good replacement for him during his absence, and overall had a very good season. Probably De Bruyne's absence was more noticeable for City and I agree that City can have an even better season, they have already done that.