You missed something, Bellingham didn't score a goal but he scored an assist for Vinicius, so statistically Bellingham contribution is very clear. I think this score proves that in the match against Dortmund without this assist, Vinicius would not have scored a goal. Regarding the arrival of Mbappe, this will create more balance. Just imagine that Vini, Bellingham and Rodrygo can win trophies, especially with Mbappe, it makes sense that Real Madrid has a bigger chance next season.
Bellingham has played a big role in Real Madrid's number of goals this season and in terms of assists even though Jude is not a front player like a striker. Bellingham's huge contribution is known by everyone since arriving from Dortmund. His assist to Vinicius in Real Madrid's second goal further established him as a figure who contributed in the final match.
Mbappe's arrival is good for increasing competition for Real Madrid's front position. But unfortunately Mbappe is not a player who is purely an attacker, but more of a winger. The competition I mean is with Vini and Rodrygo. One of the two will be eliminated if Don Carlo still sticks with the formation used for Real Madrid this season. The most likely to be eliminated is Rodrygo.