Charles may be better now than he was in his youth. But is he ever going to inspire the fondness, respect, and warm feelings that the Queen seems to evoke? I doubt it. I see him as a figurehead, serving for a brief time.
William, to me, feels potentially more problematic. Reports of his actions behind the scenes IRT Harry and Meghan, along with his and Kate's relentlessly conformist approach to the management of their public image, plus certain vaguely colonialist comments on William's part, just leave me with the impression of a somewhat reactionary personality. He will likely have a long reign, like his grandmother. I wonder how it will play out.
I think a really big difference between them and the Queen is that the Queen didn't spend all of her life with the expectation that she would be on the throne. She was "up there" in the line of succession, but it wasn't until Edward abdicated and her father unexpectedly became King that she became the heir presumptive.
IMO that has given her more of a sense of duty and service than Charles and William. It's hard to explain, because both of them are involved in lots of work on behalf of the monarchy. But both of them have been expected to be King someday, from the day they were born, and that seems to have given them more of a sense of entitlement than the Queen displays (at least in public).
CBC News network in Canada ran a special over the weekend that featured the Queen looking at, and commentating on, some of the footage from her coronation. I don't know where else it has aired. It was quite fascinating. The Queen wasn't having any of the prompts from the presenter - she shot him a steely glance or ignored him any time he tried to push her to talk about something she didn't want to talk about

But she looked really uncomfortable doing it, like she wasn't sure what she was supposed to say. A younger commentator would probably be like, oh, my dress really pinched me here, or, boy, it was hot in the cathedral, but the Queen didn't reveal anything like that.
Maybe she thought no one would be interested in those kinds of details, but she really was raised in a different era when there was a mystery around the monarchy, and it wasn't "done" to talk about yourself or have the focus on yourself.