Ruben Amorim is too attached to his principles and still wants to implement the 3-4-3 formation, we know Ten Hag legacy squad is not used to playing with that scheme, so it is no wonder they had difficulty winning. In the Europa League, Man United was lucky because the opponents they faced were not as competitive as the Premier League, so they managed to reach the final. We can see, when Man United faced Tottenham, who are also representatives of the Premier League, Ruben Amortim squad suffered another defeat. By completely overhauling the depth of Man United squad, which is in accordance with his strategic needs, I think only then can Ruben Amorim perform to meet expectations.
This is not a valid reason for their failure this season. I know quite alright, there is a specific formation that every team is familiar with but they should know that every coach has a preferred formation. Moreover, as a professional players, they are supposed to be versatile enough to be able to play with every formation that a coach chooses to use if that's what the team requires for balance.
I know there's always a perfect formation but adapting to a temporary formation shouldn't be a problem at all and should not be an excuse. Generally, Manchester united is only riding on a good luck and formation is just an extra problem but not the main problem. Amorin should not be crucified for using his preferred formation.