We might see so many upset today but I don't think Liverpool would want to take things for guaranteed. I feel they would want to keep that record and win all of their matches in their group phase of the competition. In as much as PSV might be a strong opponent I don't think they can be able to win Liverpool. If I was to bet, I would definitely bet on Liverpool to win.
If I were Arne Slot, I would rotate heavily. I would give the players who don't get much playing time a chance to show themselves and rest the starters. Liverpool have already won 7 games. Even if they leave this match with a draw, they are guaranteed to finish first. Besides, there is not much difference between 1st or 8th place except for small financial gains and coefficient points. So they have no reason to push themselves. In 2 days they play Bournemouth in the Premier League. After that there is a League Cup match. Their fixtures are already busy. It would be absurd to start this game with the ideal 11. Still, it's not easy for PSV to win the match.