I don't think if Joselu was the alternative player for Benzema because the most important thing about Joselu is his age and he is not younger than Benzema to take his place in Real Madrid for years and On the other hand Joselu was never on the same level with a player like Karim Benzema.
Real Madrid needs a player like Mbappe or other young center forwards to make them sure in the next seasons.
To be honest Joselu is very old and doesn’t have any good news to bring for Real Madrid, the last three matches i really got impressed with the middle field Bellingham in his 20 age only he managed to be the striker of LaLiga in the beginning of this season beside saving Real Madrid in their last match against Celta Vigo. The same thing with Barcelona they both need a real strong striker this season in order to do something in UCL, otherwise we going to see the English teams taking over and winning every single trophy.
Manchester City still the most strong team i can suggest taking the UCL again this season if everything stay the same way as this. But honestly this season has much less attention and competition after the big players moving out to Saudi Professional League and leaving UCL less attractive as many people loves to follow player and not clubs.