I wouldn't say that Chelsea's squad is weak. Their squad is quite strong. They have talented players like Aubameyang, Pulisic and Sterling in their attack. Aubameyang is a great player. We saw some excellent performances from Aubameyang with Barcelona. Also Pulisic and Sterling are very talented. Chelsea also has excellent players in the midfield like Enzo Fernandez and Kante. And the defense has experienced players like Thiago Silva and Koulibaly. Despite having so many talented players, Chelsea's performance was very poor.
Chelsea has sacked their coach. If their new coach is experienced, he will undoubtedly be able to strengthen the team. But the new coach also needs some time to build a friendly relationship with the team players. Real Madrid is also an experienced team. And they are in a very good rhythm. In such a situation, it is very unlikely that an unstable team like Chelsea will win against Madrid.
No one said Chelsea is a weak team, Chelsea is a big team but can't play as a solid team now.
However, if we compare Chelsea and Real Madrid, Real Madrid surely plays more solidly and has a better experience in UCL competition.
You can't expect Aubameyang to give a big contribution if he only sits on the bench. Lately, I rarely see Aubameyang played as the starter. Chelsea coach prefers to choose Felix, Sterling, or Haverts as the striker. Moreover, Aubameyang is no eligibility until June 29 in UCL. So, it is clear that he can't play in UCL against Real Madrid.
Chelsea was already in a big crisis this season in the Champions League, because after losing to Dinamo in the group stage, they were last in the group after the first 2 rounds. After that, the former coach Tuchel was fired, and the new coach Potter significantly improved Chelsea's game. Chelsea won all of their remaining group games and eventually finished first in the group. Therefore, the change of coach helped the club and saved the season in the Champions League.
Can history repeat itself with a new coach?
It is very difficult to predict how Chelsea will play against Real with a new coach, but Chelsea should not be underestimated. It is enough to remember the 2 meetings between Real and Chelsea last season in the Champions League.