It's still early to make a statement on whether or not Madrid will turn things around this season even though the start of the season has been very good but we can't say and believe that it will be like that because anything can still happen.
The presence of Bellingham can now be a good addition to the strength especially with the performance of the first 3 matches it is clear that he is very good but of course for this to be believed to be better than last season, their consistency must still be maintained and this is what Madrid must do because sometimes when the start of the season is good it is not necessarily with an increasingly busy schedule they can still be consistent and now Madrid still has to prove that especially since they also clearly want a reversal where last season did not go well for them.
You seem to have forgotten Madrid's track record so far. They are a big club that has won La Liga and even the Champions League several times. Their mentality has been formed quite well, even though after being left behind by several players like Benzema, it is very likely that they will still be able to show their best performance. So even though it's too early to say that fan optimism is well-founded. Because as fans we will see for ourselves whether Madrid is able to maintain its existence again in La Liga or not.
Vinicius Jr. is a great asset of Real Madrid and he will be one of biggest star players in La Liga too. He must be protected more by referees in the league. They must use yellow cards or red cards if fouls of defenders against Vinicius is dangerous enough. Many young players got serious injuries that destroy their career.
Brahim is like Asensio who struggles to get a good position in Real Madrid. It he won't claim a good position soon, he will be like Asensio, only a substitution for Real Madrid. Hopefully he will take this chance, from the unlucky injury of Vinicius, to make big change for his own career.
Vinicius Jr absence certainly had a big impact on Madrid attack line, because around 30% of Madrid attacks in several matches were based on Vinicius Jr agile movements. Ancelotti will definitely change his squad formation where Vinicius Jr absence needs to be covered, for example by including Diaz or Joselu. But that won't be enough to match Vinicius Jr.'s moves.