Manchester United are unbeaten in the Europa League even though they have suffered three draws which made them lose points to place the top position. Amorim seems to be prioritizing the Europa League trophy because if you look at the performance in the Premier League it will be difficult for them to catch up on the points so that the opportunity to qualify for the Champions League is only through the Europa League if they are able to emerge as champions.
Lazio and Athletic Bilbao will be strong challengers for any team because even though this is the group stage they have performed more consistently. We'll see how things pan out after the group stage is over to see if Lazio and Athletic Bilbao can make it to the semi-finals.
I think that Amorim is not in a condition to give priority to any of the tournaments, since he came to the team the results are too bad to allow themselves to choose which matches to focus on, Manchester United should win all the games now, but I doubt that this is possible. And since the opponents in the Europa League are weaker than in the Premier League, Manchester United can try to get a place in the Champions League thanks to winning this tournament, although I do not believe that Manchester United in such form is capable of this.
It may be true that a season can be saved when a team wins the Europa League as it gives you the qualification for the Champions League and a prestigious title. But to believe that a coach in Amorim's position could ever choose to neglect any of the three most important competitions in England is completely wrong. The focus usually is the Premier League, the FA Cup and the Europa/Champions League for a club like Manchester United.
The Premier League is priority 1 because that is where the fans go and watch every week or every second week in home games and fans want their team to compete for something. Giving away the Premier League is the worst that can happen and it happened to Manchester United way too early this season. It's bad for fans because they want excitement all season long. Of course Europa and Champions League are great events and can cover up some bad events from other contests, but it is not what the fans want. The fans want their team to be at the top and compete with Liverpool and Arsenal and not have their view pointed towards the relegation zone.
But Amorim can save the season to some degree with the Europa League as nobody would say it was a bad season if they were to win it. But I think they are far from winning the Europa League.