Yes we know, last season Man United showed a bad defense and was not a club that was able to compete, with the line-up of players at that time it was indeed called a club with talented players, but in reality it was just nonsense and did not present the Premier League title, only able to finish in 8th position at the end of the season.
Man United always showed bad defense in every season. They only had good defense in sir Alex Ferguson era.
After sir Alex Ferguson era, it is difficult to claim that Man United has enough talented players. Even they have talented players, the talented players always get difficulty to develop under the new managers. Man United players have bad relationship with the manager, especially with Ten Hag. It is impossible to win EPL title if Ten Hag managing style never changes. He may be good in tactical aspect, but he has a problem in mentality.
Ten Hag was unable to take advantage of it, this season the overhaul occurred again, full control in the hands of Ten Hag with the trust of the Red Devils management, the arrival of De Ligt and Mazraoui is highly expected to add depth to the squad. another thing I disagree with you and consider lenny yoro as a failed purchase for manchetser united.
I don't think Ten Hag fully controls the transfer policy. The board of Man United must have the role, too. However, their current transfer looks better than the previous one. They know which line that needs to be improved. I can appreciate that they sign few good defenders with quite affordable prices. They are no longer spend too much money for a single player. Well, De Ligt and Mazraoui are good players, it is reasonable that they can strengthen Man United defense. Meanwhile Yoro, he needs to focus recovering his injury now. It is too early to claim Yoro is a failed purchase. Before we conclude anything, just let him to play for few matches in EPL firstly.