Liverpool, Leverkusen and Milan are considered to be the favorites this season. Roma, Atalanta and Brighton are not considered favourites. Because the performance of these teams is quite erratic this season.
Leverkusen are unbeaten in the Europa League and Bundesliga so far. Despite several key players in their squad injured, Leverkusen's overall performance is still strong. So I consider Leverkusen as the favorite for the Europa League title. Liverpool team on the other hand is very strong. But I think Liverpool's main goal is to do well in the Premier League. Big teams like Liverpool have little interest in winning the Europa League title.
I don't think Milan can put in the favorite team for winning Europe League tittle, they had bad performed in domestic league and inconsistency performance become main problem with Milan difficult for winning the Europe League for this season. Most favorable Bayern Leverkusen is the winner of Europe League, unbeaten until 33 matches all competition and difficult get any teams will defeat or give first loss for Leverkusen this season.
Liverpool could be second list teams for winning Europe League, but the domestic league pressure I don't think Jurgen Klopp can focus well with Europe League and domestic league. I think he will prefers for winning Premier League than Europe League regarding how most compete with Premier League.
I know Milan's performance is somewhat erratic. But their performance is not weak. Milan have lost one match and won three of their last 5 matches in Serie A. And the team's overall performance is still strong. They have a strong squad.
Leverkusen and Liverpool are very strong. But these two teams want to win the title of Premier League and Bundesliga. And it will not be an easy task for the teams if they want to do consistently well in both places. Milan, on the other hand, have no chance of winning the Serie A title. So if this team gives their full effort to win the Europa League title then they have a chance to win the title. However, it won't be easy for either Leverkusen, Liverpool or Milan to win the Europa League title this season.