Yup, this aligns closely with my own impression of what needs doing. I'd only add to this that people need to be aware how billionaire wealth works. Nearly nobody receives just a billion in their bank account every year. Billionaires' wealth is stored in investments (normally a company they've founded, or bought, owning loads of shares, which then blow up to create unbelievable wealth). But this isn't liquid, accessible money. Billionaires use this wealth to borrow against, which banks happily do, knowing that it's safe to do so, considering the billionaire's leverage. This is one mechanism by which billionaires avoid paying taxes, for example. Here, things become tricky: How do you take this power away from the billionaire? How do you tax share ownership? There are some approaches, but I'm not sure any of them have ever been tried. If you just force the billionaire to sell 90% of their shares above 1,000,000,000 in value, the share price will plummet immediately. That doesn't really work. You could prohibit borrowing against value held in shares, but you'd somehow need to limit this to ultra-rich people. Or you somehow devalue shares held beyond 1,000,000,000, so that this isn't actually wealth the billionaire can use (to buy elections, or media companies). But then what's the point of having 299 billion worth of shares just sitting there doing nothing (in Elon's case, for example). It's a surprisingly difficult problem to solve. You could split the shares across many people. So any shares above 1,000,000,000 in value have to be divided evenly across the workforce of your company or something.

This is all theoretical though, because most billionaires would happily murder every last human being with their bare hands before giving up 0.0000000000001% of their wealth.