Speaking of the defense, every team can actually develop to be more solid in the future. Overall, every player in the main squad must be in their best form to be able to win the trophy, this applies to all contestants. The situation can change drastically if a key player gets injured. Last season, PSG was lucky to avoid serious injury problems, and all of their players were in the best condition.
Speaking of unfortunate injuries, this is where squad depth comes in and Liverpool has that especially in their attack maybe ahead of many of these teams, but I doubt they have squad on their defense which can make be at a disadvantage even any team by the way.
PSG were fortunate to have a good squad depth eith majority of the players in form and no really long term injuries woes