I agree with you. Vini is a really good player. But I also don't think Vini has the ability to score more than 30 goals in a season. Vini has played very well this season. However, he scored only 10 goals in 33 La Liga matches. Vini is not a regular scorer like Benzema and Ronaldo. Real Madrid needs a replacement for Benzema, who can score a lot of goals. Mbappe or Harry Kane could be a suitable replacement for Benzema. These two players have the ability to score a lot of goals. And their fit is very good.
Yes, Vinicius Junior is not fully reliable to replace the role of Benzema. Vini's position and play style are different and he is more comfortable playing as a wing attacker. Real Madrid still have to find a single sticker. Harry Kane, Firmino, Havertz and Osimhen are suitable substitutes to fill the position left by Benzema. But so far there has been no issue from El Real about who will be their hunting target. I think Ancelotti must immediately get a sticker without having to wait until the transfer window closure time.
Ancelotti should try his best to sign Harry Kane or Victor Osimhen. I saw Victor Osimhen's performance last season. He is a great striker. Scored 26 in Serie A and 5 in 6 Champions League matches. He can play better with an experienced squad like Madrid. Ancelotti is likely to be interested in signing Mbappe. However, PSG will not decide to sell Mbappe. PSG have plenty of money, they won't be interested in making money by selling Mbappe. And so Madrid should try to sign Kane or Victor Osimhen.