Yeah as we know against PSG Real Madrid's defense made a lot of mistakes that led to goals and this was done several times --- with a great performance from PSG to bulldoze Real Madrid mercilessly.
I'm not sure how Chelsea will do against PSG in the final, but it's likely that Chelsea will have a better match than Real Madrid, it's just that in the final many are favoring PSG as the winner.
It's understandable that many would favor PSG in the final after what we saw from them against Real Madrid. But Chelsea shouldn't be underestimated either. Their progress isn't due to mere coincidence, but rather to the hard work they've put in to get here. Honestly, I personally predict PSG will win the final and lift the Club World Cup trophy. But I'm pretty sure PSG won't be able to score many goals against Chelsea. Because I believe Chelsea's squad depth, which is quite flexible and has many options to adjust their strategy, Chelsea will at least be able to defend better. But I'm not sure whether Chelsea will be able to penetrate PSG's defense.
Yes, it is true that PSG may not win against Chelsea with such a long gap or it may be very difficult to win with them or they may lose. Chelsea are a very good team. They have worked hard to get to this point and it would not be surprising if they win the trophy in the final. However, I will bet on PSG in the final because they have shown an impressive performance against Real Madrid and they will want to keep it intact in the final. Considering the strength of the opponent, Chelsea will try to improve their defense and correct their mistakes. The final match will not be easy for PSG at all but they have great players like Ousmane Dembélé, Achraf Hakimi and Fabián Ruiz. They played impressively against Real Madrid and also will do well in the final.