I can't say if Chelsea has improved in their performance or not, it's when the new season starts is when we would know. However, their performance in CWC is impressive and their fate will be tested in the finals when they play against PSG who have destroyed and humiliated top big clubs in various leagues in recent times.
Chelsea have no doubt been impressive since last season when the season was about to end. We saw them also booking a spot in the champions league for next season which is a good progress for them from playing in the conference league last season and winning the trophy, to playing in the champions league next season.
Chelsea has also given us the best of performances in the club World Cup which makes us to have trust in them once more to have improved from the way they use to be few seasons back. The final will really test their strength and even if it doesn’t go in their favour, they look to be back in form with consistency.
I would not use the word impressive yet for their performance. In my opinion they are not yet there where they could be and want to be. In the last season it was 69 points and if it wasn't for the last few games that they won, they could have missed the Champions League qualification and worse, it could have been an 8th finish and they wouldn't have qualified for anything. Impressive is when they qualify for the top competitions without any issues, but they are not that good yet.
The game against PSG could provide some insight as I think this is a game both sites will take seriously. I wasn't so sure about most of the other games because the competition isn't as much appreciated in the heads of the players as the Premier League or cl.
Everyone is betting on PSG to win it, which is the chance for Chelsea. They could send a strong message to others by beating PSG.