After facing PSG in the second leg of the Champions League which will be played in a few days, Liverpool and Newcastle are very tough opponents for Arsenal and Southampton may be an easy opponent for Arsenal, but if you look at the results of the two teams' matches, Southampton still has several draws with Arsenal which could potentially make Arsenal unable to finish in second, third, or even fourth place. However, that is not necessarily the case because anything can still happen in a football match, because Chelsea was also able to beat Liverpool who already had the status of Premier League champions.
Yes, anything can actually happen in football, although we can only speculate. Liverpool lost today and I knew that because since they are already champions they have nothing to prove again. But on the other hand, since they have already lost this week to Chelsea, I don't think they would also want to lose again to another big team next week, that's where the problem comes in now. Even with being the champions, losing series of games wouldn't sit well with the fans especially when they are aware that they are not longer in any other competition.