PSV can be a difficult team and I really wonder how competitive they can be against Arsenal. This year, Arsenal is starting to work with Arteta to avoid making the mistakes they made last year. They managed to become a young and offensive team. I don't think PSV can withstand them.
The Champions League competition is very mentally draining so PSV can easily go down or vice versa. It depends on whether the players are ready or not to face a club as big as Arsenal which is in top condition. However, PSV's motivation is still quite high and they don't want to slump at the start of the season. I will not doubt PSV's performance in the last few matches which seems to produce solid matches. On the other hand, Arsenal also needs to reconsider, Arteta cannot make the wrong decision again because his return to the Champions League must be utilized well. At least getting through the group preliminary round in my opinion will not be too difficult when compared to other groups.
Basically, I also believe that Arsenal have a great chance to beat PSV and or, get a good result in this group stage. But at the same time, at least there will always be situations and conditions that will have an impact on the team's performance whether it is due to injuries to some of the main players and other bad events. So with that factor, then at least even though Arsenal are highly favored but still, to get good results in each match will not be easy. Because the teams that play in the Champion League certainly have good preparation too and that way, it is still not easy for Arsenal to be able to win the group but indeed, Arsenal still have a good chance.