Yes, it is true, because if big teams have any weakness, everyone finds their team's weak spot and attacks that weak spot. A coach's job is to find the weakness of their opposing team and guide the players accordingly. If big teams do not find the weakness and play in that way, it will be very bad for them. Because every team has one or the other weak spot but this spot has to be found. For those who can find these weaknesses and exploit them, winning the match becomes a little easier.
Trying to identify weaknesses in one's own team is paramount. This is followed by identifying weaknesses in the opponents they face. However, even more crucially, the coach must build a team that has no weaknesses, or only a few. This ensures that other teams cannot find their weaknesses. For example, Manchester City was a team that was difficult to find weaknesses in when they were at their best. At that time, almost every team they faced struggled to find weaknesses in Manchester City.
However, fundamentally, no team is perfect without flaws. There will always be some, even if they're small. However, a smart coach will always be able to cover up the team's weaknesses with his or her own strategy.