Frankly, I don't have high expectations from Sevilla either. They are not assertive in La Liga, and they joined UCL with their European cup win. If it wasn't for that quota, he wouldn't even be able to join the conference league. If I remember correctly, they finished in 12th place in the season.
Indeed there is Arsenal but looking at PSV and Lens I think they can compete in the 2nd place of the group phase even they can also compensate for Arsenal in this case. Sevilla sometimes surprise in European competition and last season was proof that they surprised everyone by winning the Europa Legaue.
In addition, with their destruction in La Liga now it cannot be a guarantee that they are also bad in the Champions League because Sevilla is a Champions League subscription and they can focus on the Champions League and qualify for the Knock out Phase later.