You’re confusing players ability with miss management. Not surprised a significant amount of Utd fans do it to our own players too.
Varane, Bruno, Sancho, Maguire, Rashford, Shaw, De Gea, Ronaldo are all better and more talented than most players in that arsenal squad. Under a competent coach (which we now have) many of them will show a much truer level. To Arsenals credit you have a lot of young players but currently that’s all they really are, future hopes. Many of those Utd players have shown a level only matched by those at Chelsea, Liverpool, and City, thus why we finished third, then second and have remained comfortably above arsenal bar our worst ever season.