Satoshi Nakamoto holds 1 million Bitcoin making him/her/them one of world richest individuals even if not formally recognized on rich lists. It is extremely unlikely anyone will surpass Satoshi Bitcoin holdings because their vast stash has remained untouched it would cost huge amount to buy that much Bitcoin today without affecting market and all Bitcoin transactions are public making it impossible to secretly gather such large amount.
In the future, individuals will still surpass the holdings of Satoshi Nakamoto since their wallet have been dormant with the estimated 1.1 million bitcoins, except they wake those wallets up one day and stack it with more bitcoins, that is only when Satoshi will have no challenger with most bitcoins.
While Elon Musk is big name in crypto his personal holdings are too much low than Satoshi real contenders like MicroStrategy investment funds like BlackRock ETFs or even governments. So in my point of view Elon will not be one of them or maybe on one.
Elon Musk is not a core bitcoiner even though he might have some of his wealth in bitcoin but as we know, he deals with Dogecoin for his tesla company and i even doubt that he has huge amount of money in crypto. You never can tell if Elon Musk won't become one of the influential crypto enthusiasts because he can decide to buy a huge amount of crypto and own more crypto assets than those you just mentioned.