Not only Chelsea, but Tottenham is also studying how Chelsea defeated PSG, even though in the end, they had to lose. We can see how poor Tottenham's performance was last season in the Premier League. They were at the bottom after the relegation zone. Facing PSG because they won the Europa League against United. But they almost won against PSG.
Every match will certainly have a different situation. PSG is clearly favored, and they indeed have the advantage. But Tottenham also did well. Whether Tottenham is better or PSG is declining.
It was mainly in the league that they were poor but were something else in the Europa league entirely just like their fellow English club Manchester United. For me, I still maintain that both of these clubs prioritised the Europa league more than every other competitions last season that's why they were able to go far in it more than any other competition.