Manchester is a team that are in big problems, they have been in big problems for a very long time now and I am now thinking it's more than coaching problem. Manchester United may also have some internal problems from the owners and this can cause a drop in form as we have seen .
I think a lot of improvement needs to be made and it starts now. Manchester United can't continue going to every season with this problem, they have lost the pedigree of a big team and this has affected their mentality.
Even if what you say is true but after the SAF era which was almost a decade ago ended, Manchester United have always had problems with performance and at the moment there are some situations that are difficult to explain about management but I think for the current coaching problem is also a big problem for them.
Ten Hag is one of the coaches who is still fairly good actually it's just that the problem is that he is too authoritarian in coaching which makes the players uncomfortable. In addition, there are some things that happen in management, especially about the transfer of power of the Glazer Family, which is still hampered, making the pace of Manhchester United also disturbed in this regard.
It is difficult indeed to make a difference in conditions like this because after all they have to improve structural management from above and in this case of course from ownership whose problems must be resolved immediately.