Manchester United and Tottenham are teams that have good quality overall and what happens in the domestic league will be different from what happens in the Europa League so it cannot be used as a reference and even in the last few seasons we often see teams that win the Europa League do not have a good ranking in the final standings of the domestic league maybe that will also happen to Manchester United or Tottenham.
For the opponents that will be faced in the quarter-finals I think all teams have equal quality and also in terms of percentage all teams have the same possibility to be able to win the match and advance to the semifinals.
Lyon and especially Frankfurt are tough opponents, and if Manchester United can still compete with Lyon, then I am for Tottenham, I doubt that they will be able to beat Frankfurt. The German team has a very good attack, and Tottenham is doing badly with defense, and the first match for Frankfurt will be away, which is considered better for playoff games. And if everything is clear with Postecoglou, they are already looking for a replacement for him, then for Amorim the Europa League remains important, and can determine his fate.