I think Vinicius will win the Ballon d'Or in the future. Meanwhile, last season, Ancelotti probably asked Vinicius to provide more support to Mbapp. He seemed to struggle to adapt, but Vinicius did very well. I don't think Mbappe presence will dim Vinicius light, both are crucial players who will lead Real Madrid to much success next season.
Given the popularity of these two players, it's possible Vinicius will lose his chance to win the Ballon d'Or in the future, as Mbappé is now available, perhaps with a much higher popularity rating.
Vinicius is indeed a key player for Real Madrid and has given his best so far.
While Mbappé's presence won't diminish Vinicius' overall popularity, there are times when the competition for the Ballon d'Or will become more difficult.
Real Madrid recently responded controversially, deeming the Ballon d'Or no longer relevant following last season's disappointing results.