It feels really awkward. Manchester United are 16th and Tottenham are 17th in the PL. But they are playing against each other in the EL finale. One of the weirdest scenarios ever.

But anyways... IMHO, Amorim's club is closer to the trophy. Why? Because Manchester United have a much better history in European competitions. This is my reasoning. I'm open for being surprised by Tottenham also but this is my thinking.
With Manchester United and Tottenham success in reaching the final, the Europa League looks less competitive. It's hard to accept but that's the reality, Manchester United and Tottenham journey this season has surprised and amazed many people, they are like different teams when competing in the Europa League. In the last few seasons, there have been many surprises in the Europa League.
Based on experience, Manchester United is indeed more worthy of being the favorite than Tottenham, their efforts to reach the final are much harder, while Tottenham are lucky to have an easier path. It would be very sad if Manchester United loses, Ruben Amorim will risk everything to win the trophy. Looking at the condition of the team, it seems that both managers can field their best starting XI.