Almost 10 years Man United did not win the EPL. Even 7 coaches have been selected to try to deliver the championship title but failed. After Sir Alex Retirement, Man United did look bad. In fact, many large transfers have ended up failing. When Ten Hag arrived, they began to improve even though they did not have a championship but Man United's performances were promising. They have made good use of transfers, but there is one player who could possibly be the solution. Since they currently do not have a number 9 striker, Maybe Man United can buy Kane as this solution. But Tottenham are unlikely to release Kane to an English club.
It was a very good team in the 2000s, but as you said, after Alex Ferguson left, the team moved away from its former quality. No matter how good coaches came and how many good players they bought, they could not reach the level of champions. I hope they can get back to their old days as soon as possible, it used to be one of my favorite teams, but we are far from those days now

It's true that manchester united in the early 2000s was terrible with all the great players around at that time and it was almost certain that when they played, victory was guaranteed. Sir Alex Ferguson is a phenomenal figure as a Manchester United coach and until now there has been no coach who can replace him. I think Manchester United will be very jealous of the achievements of their city rivals who have always dominated the EPL in the last 10 years and Manchester United must be able to prove their strength again later in the Erik ten Hag era which is considered to have a very big impact on the club.