Under President Eisenhower -- the last decent Republican President -- the top bracket was 91%. The highest ever was in 1944 @ 94% for people making over $200k. The average salary in 1944 was $2,410. Those taxed at 94% made at least $12,000 after taxes, about 5 times what the average American made.
Senator Elizabeth Warren proposed -- I think -- a 70% tax on only the income over $200k. So that first $200k is taxed considerably lower, say 40%. $120K after taxes. If you make $300k, only that last $100k would be taxed at 70%, so you'd take home another $30k after taxes. $120k + $30k = $150k. Someone who made $1 million would get $360k after taxes, which is still almost 5 times the average 2020 income of $78.5k.
Now, I'm not endorsing those exact numbers, but I very much like the structure. If resources are finite, there's a point where having X amount of it is inherently harmful to others. It's a form of violence in my book, far worse than taking someone's wallet at gunpoint. I forget who said it -- probably AOC or someone else you wouldn't respect -- but I agree: "Nobody earns a billion dollars. They take it."
How much freedom do we give any one person before it starts encroaching on others' freedom? You can't shoot a gun in your backyard within city limits. You can't play your music as loud as you want in the middle of the night in a neighborhood. You can't cut through my yard without permission. You can't dig a well without a permit because of the potential impact on existing wells. Nobody needs a billion dollars. Nobody deserves a billion dollars. If a billionaire gives up 70% of 1 billion, they still have $300 million. I don't pity them in the slightest.