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.
So true! I don't see a reason for Amorim to put his focus onto premier league. He has his chance to win the trophy at europa league, and should give everything he has to win it. He should lower his expectation to premier league, then increase his pressure to his players in having higher target on europa league.
This may be working as his team will able to get trophy + european spot for the next season. He shall lower his premier target to be "not relegated". However, i think his club is literally safe from being relegated.
I see no reason for him to pressure his club on premier league. It may be working in decreasing his club's burden and get bigger motivation to win europa league.