Unfortunately they have never been that great at UCL, it hasn't been something that common and we can't really see them doing anything this season neither. They got pretty close last season, at semi finals they were playing against Dortmund and they had plenty of shots either saved by the goalkeeper or hit the woodwork, they got very unlucky, otherwise they could have been at the finals, not that I think they could have beaten Real Madrid to be fair, but at least could have been one step closer and a few lucky stuff could have made them win.
This season they do not look even that close, I do not think they will reach semi finals, they are having trouble at group stages and there is a very real possibility that they may miss out and be outside of top 24, which is hugely disappointing considering how much they are spending each year. I can't really point out how much problems that could cause as well, they need to do a lot better for their future.
You said it, I know it's not serious to say that it's due to lack of luck, because luck is a factor that many don't consider but it does have a lot of effects, so PSG in the UCL not even with the strongest offensive trident for a moment could not win the UCL, and that was despite the fact that there was a lot of support, I remember those big bets for PSG to win the UCL titles that many contested with good players and were not even close to winning, the truth is disappointing, but that's football, if they don't achieve anything this time it will be a hard blow for this team, they are not very good and their recovery is very strong.
We are not going to say that PSG was unlucky because they didn't reach the finals and lost it. From my own understanding, I feel that we are the ones giving PSG too much hype because they don't have a rival in their domestic league. We think that they are very strong, but they come to UCL and mess things up for themselves. PSG need more improvement in order for them to have the chance to win UCL.