Both Real Madrid and Chelsea seem to have no serious intention to sign Benzema. There is no big advantage to have him in the squad. Benzema even failed to play well in Saudi, how can expect him to play well in Europe? Real Madrid focuses to sign young strikers, their targets are Mbappe and Osimhen. Meanwhile Chelsea already have Nicolas Jackson. Chelsea also prefers to sign young strikers.
The era of Benzema was over, he is no longer in the prime age. Why he must return to Europe now?

Real Madrid right now needs nobody but Kylian Mbappe and the return of the young Brazilian talented player Endrick. They're no longer in terms of a possible return for Karim Benzema to the club, they're building the club around for the future. Bringing Karim Benzema back kills that honestly and it's far from happening.
They will be the best side next season yet again if they go ahead signing Alphonso Davies, Trent Alexander Arnold, and lastly Kylian Mbappe. These are the names needed to push them to win the treble next season.
For Chelsea, they'll be no other player than Victor Oshime, they have to make him the number one priority whenever the new transfer window begins. they already have that good relationship with Napoli, coming to agreement won't be difficult.