Liverpool have been the most consistent team in UCL so far with 5 perfect wins to be at the top of the UCL standings, with the performance they are showing at the moment of course indicates that the change in UCL format has absolutely no effect on them, while girona, although they were able to surprise us last season in La Liga but their performance this season in UCL is quite bad with only get 1 win from 5 matches, with the difference in performance and team quality of course Liverpool can win the match and my prediction that Arne Slot'squad can win with a score of 3-1 against Girona in the 6th UCL match later.
In other words for me Girona is not fully ready to compete in the Champions League. I mean Girona goal this season is just to gain more experience by playing against big European teams. Their first season in the Champions League is not about whether they will advance to the next round or not, but how much Girona can learn from their opponents game. The final result even if Girona loses will not be considered bad.
Their first season in this competition is more about gaining experience and understanding the intensity of competition that takes place in the UCL with against big teams, so indeed they can't do too much in the UCL when facing strong teams, like as Feyenoord, PSG and eindhoven who have experience and better performance in the UCL, however, like your said, the experience Girona have gained from UCL games this season will be invaluable for their future development, although there is no guarantee that they will be able to qualify for the UCL again if remember their inconsistent form in La Liga so far.