Fair enough.I don't think his age has anything to do with; he's still a machine.
What will make the difference, IMHO, is the attitude of the competition.
Alcaraz now knows that he can get into Novak's head.
And Novak knows that Carlos knows this too.
If / when the likes of Stefanos, Daniil, Holger and Casper gain the confidence to beat Novak (rather than go into the games already defeated), his time will then be done.
IMHO.
But age can creep up slowly or catch you out quickly. In 2021, Ronaldo was in fair form for United but by the time it came to the World Cup in December his legs were gone. Djokovic is 36 and for him to become Wimbledon champion at the age of 40 is plainly madness - but if anyone can do it, it's himself.