Try to go deep on whose fault it was, why Ten Hag did not succeed at Manchester United. I won't be among those who don't think Manchester United have a problem with players than they do with coaches, how many changes and signings of new managers are they going to do while blaming coaches for all the failures. Amorim has been handed the club what did he do in his first season, the players are the initial problem of Manchester United, if they want some upgrade, then it should begin with committing to better signings.
I don't understand your logic at all. Let's check the timing: Ten Hag comes to United and with the players he didn't choose and who he doesn't want (whom he then kicked out) he makes serious progress. Then he makes 400+ million signings and the club (with the players he wanted) sinks. If we're to blame someone for United having bad players, it's him, isn't it? Of course, the problem is complex (he was not the only one who approved the signings), but a significant part of his guilt is undeniable.