It is very easy to answer (and impossible to actually do). Two things:
1. Progressive taxation scale. Not the fake system we have in every developed country, but the real progressive system, which doesn't end at the minuscule sum of 100-200k, but is proportional until the infinity, certainly into the billions.
2. "Ban" offshores and tax heavens.
If this has happened somehow magically a vast majority of the financial issues would go away immediately.
Simultaneously, an unfathomably large sum of money would become available in use-it-or-lose-it fashion to the billionaires. Political spending on the 2020 election was about $15 billion, while you're advocating a system that would substationally rebalance a $4.4 trillion national revenue stream. Do you think that the rich would spend more than $15 billion fighting that? Bezos made $70 billion this year and in previous years had an effective tax rate of about 0.9%. Increase that rate to 37% - or extrapolate a curve forward from $578k - and if he succeeded then by himself he could profitably spend more fighting this proposal than Biden, Trump, and every super PAC spent in 2020.
1. Progressive taxation scale. Not the fake system we have in every developed country, but the real progressive system, which doesn't end at the minuscule sum of 100-200k, but is proportional until the infinity, certainly into the billions.
2. "Ban" offshores and tax heavens.
If this has happened somehow magically a vast majority of the financial issues would go away immediately.