Man United spent a lot of money this season but if we look at where they stand now, it seems that the squad that Ten Hag is building is still inadequate. Ten Hag should know very well that Man United's defense is a weakness that must be addressed immediately. Instead of signing a quality defender, Ten Hag prefers to bring in a goalkeeper, striker, and 2 new midfielders. Indeed, there are Jonny Evans and Sergio Reguilon, but that is not a solution to Man United's backline problems because what Man United needs is a strong, world-class defender.
Ten Hag might not be the right one for the job. What saved him was the result of last season, which was possible because Tottenham, Chelsea and Liverpool played a weak season. What if they played a better season? I am sure that Manchester United would not have qualified for the Champions League. Money is kind of irrelevant as some teams now prove with their performances. First and foremost Chelsea of course, but money is most effective when it is in the hands of a manager who understands all the details of his team. I don't think that an extra 200m would get ten Hag very far.
I think what you said is not correct because Erik Ten Hag has not been able to maximize Manchester United's game this season due to the large number of injured players which has made Erik Ten Hag difficult in managing his strategy. Therefore I am quite surprised if you say Erik Ten Hag is not the right coach for the job.
However, sometimes fans still don't want to accept the situation and they immediately express their annoyance by blaming the players or coaches. But that's up to them, which means Erik Ten Hag needs time to bring Manchester back to its glory like during the Ferguson era. Polishing the squad to become stronger definitely takes time and Erik Ten Hag must be patient with all these tough tests.