Undoubtedly, a player like Karim Benzema left Real Madrid and Real Madrid could not recruit another star in that position which can be considered as a weak point for Real Madrid. After Karim Benzema left Real Madrid, Real Madrid lost their first two friendlies and everyone feared that a bad season might be in store for Real Madrid, but as the season started, Real Madrid returned to their former form. Real Madrid have played three matches so far in La Liga where Real Madrid have won the first three matches. Real Madrid will do well without Karim Benzema in the Champions League if they can maintain their current performance in La Liga.
We cannot rule out that Bellingham has contributed greatly in their three matches in their domestic competition. However, we can't measure how consistent they are when playing match after match. yep, considering that the 2023/2024 league has just started, they still have many matches to play. Madrid haven't found a team strong enough for them to play against, maybe there aren't many competitors in La Liga. but in this competition, there are several teams that are ready to face Madrid especially without Benzema in their squad.
IMO, Ancelotti cannot always rely on Bellingham as a determinant of their victory. I'm pretty sure Carlo Ancelotti knows that very well. no one doubts Bellingham, it's just that he is still very young, it doesn't even rule out the possibility that this player will experience ups and downs in his game. that's why, Ancelotti needs some plans against a team that is strong enough for them.
otherwise, other strong teams could become a barrier for Madrid in this competition. besides that, Ancelotti must increasingly create a strong chemistry between Vini jr, Rodrygo and Jude Bellingham. thus, Carlo Ancelotti could have relied on them for Madrid's front line. but still, Ancelotti must have some other plans. especially, if you meet other strong teams like Bayern, Manchester City, and even other teams. well, because this competition hasn't started yet, it's best if we just turn our attention to the domestic league that will be played by Real Madrid.