Courtois wanted to avoid Manchester City and Chelsea. Sure everybody would prefer Benfica, Inter or Milan. I think they should be thankful they didn't draw other big teams. I'd put Chelsea fourth place after these three mentioned team. This round may not be that difficult for Real Madrid, who eliminated another English club Liverpool. I can't say same thing about their possible semi final match-up though.
Barcelona have won 3 El Clasico matches so far this season against Real Madrid (Spanish Super Cup Final, Copa Del Rey and La Liga), this is very important for Chelsea, especially about how Barcelona overcomes Real Madrid's and take advantage their weaknesses.
Chelsea must realize that Vinicius and Benzema are two players who need to stop their movements. Their individual skills very often make the opposing team concede and lose a match, so if Chelsea manage to overcome these two players then of course they will succeed in minimizing the possibility of conceding goals. But Real Madrid is not only about those two players, Asensio and Rodrygo are also dangerous but these two players are not really getting a place in the main line-up. I think Chelsea must appear different from Liverpool, so they also need to learn a lot from Liverpool's mistakes against Real Madrid so that there is still a chance of reaching the semi-finals.