Many will take the betting option that Manchester United will win in the continuation of the UEFA Europa League, but I think like you that on paper Manchester United can still be relied on because Manchester United is a famous team that plays in a famous league, while their opponents are not followed like they follow Manchester United.
Behind that, I have a feeling that Manchester United will not easily win as favored because this match is not taking place in England but in the Czech Republic.
It seems that there is no need to consider it anymore, betting on Man Utd in this match is the right decision. Although both teams in the standings have the same points and the overall statistics are not much different, but when compared in terms of experience and also the tight competition that each team has participated in, Man Utd is clearly above them, in this match Viktoria Plzen only benefits from acting as the host, I think that's the only advantage Viktoria has to at least hold Man Utd to a draw.