Leverkusen's chances of losing this match are no greater than Atalanta's. They were favorites from the start and their record without defeat in 49 matches proves that they will be very difficult to beat this season.
Xabi Alonso has succeeded in a good mentality with Leverkusen, that is the main asset for them. Apart from that, the chemistry that has been built between the players is also one of the factors that has made Leverkusen's play so solid this season.
I think they will win the Europa League this season.
Atlanta also have reached the final round after a difficult journey they went through, from the start not being favourites as finalists of course Atlanta was able to surprise us with their achievements that were able to reach the final, at the moment Atlanta is certainly not the favorite to win the Europa League when they meet Leverkusen later, but I think Atlanta will also probably provide a strong fight for Leverkusen, If if they win in the final, Atlanta of course must remain focused on the match until the referee blows the whistle because as you said Leverkusen often give surprises until the last minute of the game.