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.
I think the book markers are considering the Liverpool Manager doing that already that's why the odd of the Liverpool team to when is higher than that of their opponent PSG, Liverpool has already qualified for the next round of the champions league the manager will have to give some of the players a chance start tonight while Mo Salah and some regular starters may be rested or maybe used in the second half. I don't know about the financial difference between the 1st and the 8th position but Liverpool can still use the players to win Psv despite playing from away.
Liverpool Manager will also consider their chances in the premier league during the weekend, they are in the first place in the league they have right schedules they will do everything possible to avoid defeat in the domestic league to avoid Arsenal catching up with them.