Before facing Lyon in the Europa League quarter-finals, United will still face two teams that will not be easy to face, Nottingham and Man City. United players' confidence may currently increase from the last few matches, winning against Sociedad, drawing with Arsenal, and beating Leicester with a score of 0-3.
Players' confidence will be better if United manages to win or at least get a result that is not lost from the two matches before facing Lyon. As a coach, I am sure Amorim will not only think about the Europa League. Even though there is no hope in the Premier League, he will still do his best.
Maybe Amorim might have other thoughts, but if I were him I would put all my eggs in one basket, which means prioritizing the Europa League above all else because that is the only best way if Man United wants a trophy this season. All that remains and needs to be done in the Premier League is just to avoid relegation and I think it doesn't need special attention because the gap between Man United and Ipswich who are now in 18th place is 20 points, while there are only 9 Premier League matches left.