You are right. At the start of the season, Manchester City may not have expected to win the Premier League title. Because Arsenal was in very good form. And were almost 10 points ahead of City in Manchester. But Arenal's sudden loss of form made Manchester City's chance to win the title. Arsenal lost points in 6 of the last 10 matches. On the other hand, Manchester City was able to maintain the consistency of their performance. The team was able to win the title by consistently scoring points in every match. However, if Arsenal's performance was stable, Manchester City would not have won the title.
The English premier league is survival for the fittest. Consistency is the only active factor that matters in football, especially in elevated competitions. Arsenal lacks the consistency to keep winning games, ceding points to mediocre clubs, and bargaining with equal strength in the last days of the Premier League season. Pep Guardiola knows his former colleague's weaknesses and made advantage of them, streak winning games and putting the gunners' confidence fully on the point of defeats, meeting them numerous times and winning them in all phases.
I agree with you. If you want to win the Premier League title, you have to play consistently well. The fitness of the squad players must be good. If the fitness of the squad players is not good, it will definitely affect the performance of the team. Several key Arsenal players have missed a number of matches due to injuries this season. This has affected Arsenal's performance. The team lost points in many matches. And they are not able to return to the truck. And so if Arsenal are to aim for the title next season, they will need to build a strong squad capable of consistently performing well.