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.
@KTChampions to be fair the new coach of Chelsea deserves time at least one proper full season before we start to judge his work, and currently I feel that both teams are equal but if I had to pick one team out of these two for proceeding to the next round then I would pick Dortmund because Jude Bellingham is playing for them.
Lastly getting Ronaldo would be a huge blunder on Chelseas part, because these days he plays less and causes more distraction by his off field activities hence they should avoid this transfer and try for other players wholl be committed to their coach/club.
If Potter doesn't change the trajectory Chelsea took under Tuchel, he won't have another season. These are the modern realities - you do not have time to "prepare", you must immediately show at least some result, and if it is good, you have a chance to work further to show an even better result.
Signing Ronaldo will most likely be a marketing ploy, but with all his age he has not lost his sense of goal and he still has a shot, so in some games even without playing all 90 minutes he can be useful.