I don't think with Arsenal and Barcelona only are the team have favorite for Europe League winner because still have Juventus back to consistency performance at last six matches, right now Europe League tittle race most competitive for winning the second competition level on European. Honestly, Arsenal have better quite appearance in this season at domestic league and European League but I doubt can consistency because next round of European League begin on February next years.
Many predicting the winner of European League between Barcelona and Arsenal but the problem right now Barcelona have against with United on play off round.
I put Arsenal as the main favorite club compared to Barcelona and Juventus. Why? Because Barcelona and Juventus still have to go through the play-off round first, everything is possible, right? Especially for Barcelona because they have to deal with a club that will be difficult for them to beat Manchester United under Erik Ten Hag who is starting to show improvement. Manchester United also has the right to be the favorite status because it is one of the big clubs in the Europa League this season. Meanwhile, other clubs that were knocked out of the Champions League who will compete in the play-off round such as Ajax Amsterdam, Bayer Leverkusen, Salzburg, Sevilla, Shakhtar Donetsk, Sporting CP will also provide fierce competition in my opinion, although there are several clubs that are currently in a slump like Sevilla represents La Liga and Bayern Leverkusen represents the Bundesliga.