Despite that Liverpool have qualified, I was not expecting the betting company to give high odd to Liverpool against PSV. Looking at Liverpool's performances right from the ground, and even comparing the two teams' performance statistics based here in the Champions League and also in their domestic leagues, I think that Liverpool have better statistics and performances than PSV.
The bookies know what they're doing and if I were you, I'd avoid betting on Liverpool to win. They might likely lose the match because they've already qualified and I don't expect them to give the game much importance. So I expect Arne Slot to play his second eleven against PSV and that's the reason for the bigger odd.
However, the truth is that there must be a reason why Liverpool have higher odds. Maybe it's due to the set of players Liverpool will use. But even with that, based on Liverpool's lineup that I am seeing, PSV still should not be the favorable team to win based on the odds.
I don't think what you saw is the real line up for the match because line ups are usually made public an hour or two before kick off.