I personally think Idris Elba is way too old as well, but he has been persistently mentioned for the last 10 years, which is why I said they may give him a one film contract. The concept would be a place holder, as Elba has been a well established actor for 22 years and would probably only want to do one film, anyway. If EON was not bowled over by any of the young candidates who audition for the part, Elba would be a kind of one film insurance policy, if you will.
But that's not been the history, and it's unlikely to happen. Craig was in the role for 16 years and 5 films, and probably aged out of the role in his last 2 movies. Fortunately for him, he has found a better character to play in the Knives Out franchise, Benoit Blanc, as far as showcasing his acting abilities. He has signed to do a third film and may end up doing as many Blanc films as Bond films. The character is not limited by age.
Ideally, you want someone slightly younger than Craig when he got the Bond role, who can also do 5 films in a 15-16 year span. Craig was already close to 40 when he got the role, so I think the person they hire should be early 30s, no older than 35. For comparative purposes, Sean Connery did 7 Bond films in 21 years. But Connery was cast in the first Bond film when he was just 31 years old, enabling that longevity.