Chelsea still have to prove how good they can be in the Champions League, despite the fact that they won the Club World Cup, no one took this tournament seriously, perhaps with the exception of the last playoff games, but the tournament still remains not very status. The Conference League, which Chelsea won, is also a low-status tournament and Chelsea had to win it, so in order for them to start being taken seriously, they need to play well in the Champions League, but for now it is too early to talk about their strength.
Yes, I agree with you, it is too early to conclude that Chelsea will perform well in the Champions League this season, especially because the tournament they won has been viewed as a low competition. The FIFA Club World Cup is not a competition in which all of the top five clubs from each league compete, so Chelsea may benefit because they did not face any serious opponents from the start of the tournament. The Conference League is also a low competition, and if Real Betis had maintained their lead, they may have won the trophy.
Many people believe Chelsea would struggle to qualify from the Champions League group stage, but I've been impressed by their recent performances, which is why I believe they may do well in the Champions League this season. But, as you said, they have to show themselves by playing in the tournament since we don't know if any of the players will be fatigued after playing some of the league games, as we saw with Palmer at the end of last season, who struggled to score goals.