The match will take place home and away, Sevilla's chances are still not closed and it depends on how the first leg goes. After all, Sevilla are very familiar with the European league and they have a different mentality when playing in the Europa League, so the match will be difficult to predict and Manchester United will also not easily get points in two matches.
But if you count the strength of the players and the consistency in their respective leagues, then I'm sure no one thinks Sevilla has a chance of beating Manchester United except for the Sevilla fans themselves. Head to head as you said is also different from the condition of the club at that time, so the potential for future matches will be much different.
One unique fact about the competition for Spanish representatives vs British representatives in Europe is that English teams have never been comfortable meeting Spanish teams. Even though they sometimes beat the Spanish team, they always get matched resistance.
In this case, no one should underestimate Sevilla because this team has a good record in the Europa League. Manchester United are aware of it and everything will be decided in 2x90 minutes because there are away and home matches. I hope Sevilla plays well so that this match will not be boring to look forward to.