Benzema is the spearhead of Real Madrid whose form was absolutely stunning last season and when Benzema can't play due to injury or other reasons, it will at least affect Real Madrid's performance. I think Carlo Ancelotti has already realized that and most likely he already has targets for the next winter transfer window. If we look at the character of Ancelotti, he will only sign players if the team's performance shows that it is necessary. But considering that Benzema is not young anymore, there will come a time when Real Madrid will be in that situation.
Actually Real Madrid had the option to bring in new players in the transfer market last summer, especially in the striker position. however, Perez insists that his team is not currently experiencing a striker crisis. but as you said, having Karim Benzema injured will certainly affect Real Madrid's performance. without underestimating Benzema's ability, but renewal of players is a priority for Real Madrid going forward.
and Don Carlo has realized that, it looks like there are several players who have been targeted and made on the list in the next winter transfer window.
In addition to looking for a replacement for Benzema, who is no longer young, Real Madrid inevitably has to bring in newcomers. and yes, Mbappe is one of the players who meet the criteria as a future Real Madrid striker.