Biden's proposed 43.4% tax on selling appreciated assets (without offsetting losses) makes no sense. Only fools or those facing bankruptcy would sell. His 43.4% CGT at death wouldn't change that unless death seemed imminent. Even then it wouldn't work: Those wealthy enough to be affected are already setting-up family foundations to stash appreciated assets (and employ relatives).
The nation did all right with a capital gains tax of 15-25% since 1938, with the horrible exception of the stagflationary late seventies when rates up to 40% brought in much less real revenue than the Bush 15% rate did.
The great John Goodman makes a typically strong argument that the conceptually proper and economically efficient capital gains tax would be zero.
Link to Goodman piece : https://www.forbes.com/sites/johngoodman/2021/04/30/the-ideal-capital-gains-tax-rate-zero