In my opinion, they just need players to fill the void when Benzema can't play. Because as we have seen, when Benzema was absent Real Madrid lost a figure up front. Vini and Rodrigo are good, but it's not enough to replace Benzema's role up front. A few times they have played without Benzema and as a result they have struggled to score goals, this is a job to do well.
They may need someone to replace when Benzema can't play well anymore, but they shouldn't get a striker on the season when Benzema may get the ballon d'or, I mean dude lead the UCL goals, led the league in goals and led the league in assists if I am not wrong, or he was up in both of them at least. So that is a proof enough to know that dude was playing like he never played before, he has been far better than superb.
Don't get me wrong, get some 20 year old from brazil that will play well in the future, nobody says don't do that, but to get Mbappe when Benzema playing like this, and paying 50+ million for him each year and paying like 100 million signing bonus? That would be the wrong move.