Of course Liverpool are more favored to win the match when they meet PSG in the Champions League because the competitive level of the teams in the Premier League is very different from the competitive level of the teams in Ligue 1. So it is quite natural for many people to be more confident in Liverpool than in PSG because even though both are teams that are currently ranked first in their respective leagues, Liverpool has more ability in terms of beating any opponent at this time.
Not only in the domestic league, Liverpool is a team that has managed to be at the top of the Champions League qualifying round. Liverpool has only lost 1 out of 8 matches, while PSG has a different situation. The first leg will take place at PSG's home ground, not meaning it will be a big advantage for PSG, but it will be a match that will be quite difficult for both teams. If Liverpool can win the first leg by a margin of 2 goals, they will be quite comfortable in the second leg when playing at home and can ensure a ticket to the next round.
Arne Slot fielded a second string squad in the final League Phase match against PSV, which resulted in their defeat. In my opinion, if Arne Slot had not rotated his squad, we might have seen Liverpool leading the standings with 24 points. Meanwhile, PSG had a very hard time reaching the round of 16, so it is natural that they are not the favorites when facing Liverpool. Of course, I don't mean to underestimate PSG, but on paper Liverpool are more worthy of being the favorites.