Arsenal are of course favorites to win the match based on the odds on offer - but however, Manchester United is a team that is trying to wake up and improve its performance. Ruben Amorim was brought in to help with many of Manchester United's big plans for the remainder of the season - so I'm not entirely sure Arsenal's odds today are favourable.
Manchester United actually saw what Ruben Amorim did with Sporting Lisbon, were impressed with his management in Sporting Lisbon and they decided to sack Ten Hag and hire Ruben Amorim. It's because they believe this young coach can help them to have a successful chapter, after many chaotic years with lot of money used but there are limited short term success.
On the one hand, Arsenal is trying to get an additional 3 points to increase the pressure on Liverpool - but I think Arsenal also need to be alert. As far as I know, Arsenal have failed to win against Manchester United for the 4th time in a row - that is a fact that is quite difficult to solve. If Arsenal win at home today - then of course they will already hold a new record. About Liverpool - I believe 3 points in away match is winnable.
Arsenal are stronger than Manchester United and they have already worked with Arteta for several seasons. It's big advantage of Arsenal against Manchester United because it's hard for a new coach who comes in mid of season, can quickly pay his management and tactical marks on a new club.
Arsenal in this season play less stable and impressive than two latest seasons. This can be great hope for Ruben Amorim and Manchester United to find a win in this match, they are weaker than Arsenal but they have enough play resources to compete against this opponent.