If you look at the performance of the two teams in the previous matches and also because this match was played at the Emirates Stadium, Arsenal's home ground, so I think it's quite natural that Arsenal are favored by the betting exchange.
But I plan to do something different, I think the odds @ 4.10 for Manchester United's victory are quite worth trying with a level of risk that is quite worth it with the possible benefits that will be obtained.
This is a match between two top teams, everything is possible.
I understand your point and it's true that anything can happen in this big match we can take an example from the match between Newcastle vs Liverpool
when Newcastle was supported by the betting market but in the end Liverpool ended the match with a win the same could happen to Manchester United who knows
I will follow your bet with a separate slip I mean 2 bet as backup one of them is over on the total goals.