You are right PSG has struggled in UEFA Champions League lately. They have lost to Arsenal and Atlético Madrid, and tied with PSV. Bayern Munich has stronger team and better winning record giving them an advantage. However PSG still has Kylian Mbappe who can change game. Although Mbappe has not led PSG to Champions League victory he remains threat. This matchup is exciting. Bayern Munich consistency might be too much for PSG but Mbappe could pull off an upset.
In this season, PSG have downtrend performance in UEFA Champion League after playing four matches have defeated 2 matches and 1 being by having four points. Out from the playoff round position make PSG must secure all three points left and facing Bayern Munich become difficult match will easily get three points or not.
PSG have defeated by Arsenal and Atletico Madrid, only one winning match when facing Girona but being draw when facing PSV make difficult position how to break the higher standings place. I don't think easily for PSG to secure the top eighth position standings behind four matches left have to face Bayern Munich, Salzburg, Manchester City and VfB Stuttgart.