Not only the Manchester United vs Lyon match but in all the quarter-final matches I don't think any team is favored too much, I think all teams in the Europa League now have the same chance to qualify for the semifinals.
I think the same as you, for me they have the same chances of doing things well, MU is flying in the Europa League, I don't think it's bad but they should play with the same intensity in the PL, however things are different now because Lyon is in need and they will go all out, it's their chance, they also dream of winning this competition, I will like to watch this game since they are the most exciting, for me these games are the ones that contain the most spicy football because both will be looking to win.