I'm already imagining Sevilla in the Europa League after the group stage. Because even if they deal with Lens I don't think they can do the same as for PSV. I don't even mention Arsenal because I believe Sevilla don't have a chance against them. Arsenal can beat them home and away both. Sevilla should be grateful if they get one point home at least.
As for PSV they seem far stronger than Sevilla now. Their way of demolishing Rangers home was really impressive. I think PSV can get at least 4 points from Sevilla without exaggeration. Sevilla would finish the group as the third and fight for the Europa League title again.
I think group B is inhabited by balanced clubs, it's true that Arsenal have become more superior after their movements in the last transfer market. If you look at group B, at first glance it looks like a club that usually plays in the Europa League competition. However, all clubs have experienced a lot of growth after buying and selling players this summer. I favor Arsenal and PSV to qualify for the next round, Sevilla and Lens are still very much in doubt.
Arsenal have been very successful in the EPL so far, they just beat Man United 3-1. It is possible that Arteta's squad will wipe out all the matches in the group phase with a win, let's wait for their action.