When we say as a bettor, in this case, looking at the odds that Manchester United now has, with 4.20, it looks good, but this time the Play off at Camp Nou clearly won't go as smoothly as expected.
Regardless of anything, seeing their H2H and playing at home is clearly very profitable for Barcelona for the first leg.
I don't think maximizing a draw at Camp Nou is not a big problem but to make it a win for Manchester United I think it's a bit difficult.
If referring to the available odds, I would bet on Barcelona. IMO, maximizing a draw is quite difficult for The Red Devils. the reason is, this fight will be fierce and how the two coaches will collide tactics. The problem that Man United will face is how they counter the Barcelona midfielders. United, will prefer to play with a counter-attack tactical scheme, like during the Man United match against Arsenal. so, it looks like Ten Hag will tighten up more in their defense line.
Different from Barcelona, besides they have a good record when they meet United. I'm sure Barcelona will give a surprise like the Supercopa de Espana final when they met Real Madrid. but, this is just my scenario. In fact, we don't even know what the two coaches will do when this match is held. however, at least Barcelona has the advantage of playing as the home team in the first leg.