I think that people wants Manchester United to play as best as possible in any kind of match and never do experiment except in training, while the reality experiment must be tried in everything, start from training, friendly match and then the official match if it works.
Expecting a strategy will work after it successfully in training isn't make sense because the pressure is completely different.
I have no issue to see a team lose against weak team in friendly match.
Enough to discuss this friendly match on which nothing depends and which Manchester United did not play with the main squad, otherwise ten Hag will be fired because of this defeat.
If you want to discuss the result of friendly matches, then at least wait that the team plays them with the main squad, where ten Hag will change only a few players and will perceive these matches as a test of the strength of the team. I see that Manchester United has potential, there is ambition, there is desire, this is a young team that lacks a little experience, besides that they have almost everything they need. Maybe a win over City will give them the confidence they need, I don't think it works that way but I'd like it to.