Apart from Arsenal, Barcelona, and Juventus, I don't see any other strong contender that is capable of stopping Manchester united in the Europa league. Eric Ten Hag has done a great job so far, and I believe he is setting every system to go for the Europa league title. Manchester United is so hungry to get a title for some seasons now, it will be so good to see them register another Europa league title after the last one in 2017 in Sweden.
Feyenoord and Real Sociedad are strong clubs too and both of them can compete against top clubs, you shouldn't really confident to see Manchester United will become a champion because their first step is need to beat Barcelona first, Barcelona is strong and have beat Real Madrid in this season. Juventus actually a bad club in this season, the management have an internal problem and it will cause the players get pressure too.
I understand why he believes so much that Man United will be able to win the UEFA Europa League this season, Man United appeared impressive after the arrival of their new coach but I also agree that Barcelona will be their toughest hurdle, the two teams are currently on the same graphic which can be said to be uphill and only a manager who can read the weaknesses of the opposing team who can finally win and advance to the next round in this tournament and that is difficult to predict.
Juventus are having a different story this season, the sanctions they receive seem to damage the mentality of the players so that in this tournament they are not so considered as strong contenders for the championship.