Indeed, Chelsea performed well in the UCL. They have a chance to win like Tuchel. But with the current conditions I doubt it. I don't think current players can compete with Man City, Munich or other big clubs. In 1/16 they will play Dortmund. I don't underestimate Chelsea, but Dortmund can always surprise. Chelsea must be vigilant. Even though that game is still a long way off, there is a chance Chelsea make a big transfer maybe that could change the chances of getting to the Final.
I don't think that any transfer can seriously change the chances of the teams (unless of course it's Haaland + Mbappe, but they hardly want Chelsea plus they can no longer play for another club in the Champions League this season). Maybe we will see Ronaldo's move that has been talked about so much? He's not showing anything special this season, but he has a certain Champions League magic associated with him.
Bringing in players who are already registered in the Champions League with other clubs cannot help Chelsea, they can only play in the domestic league, while the Champions League must wait for next season. Ronaldo is very likely to be played in the Champions League because the club that Ronaldo defended before did not qualify for the Champions League. This situation can be used by Chelsea to increase their strength to compete in the Champions League. Ronaldo really can't do much and isn't as sharp as he used to be, but his experience and skills can help Chelsea go a step further.