Main problem with this is that unemployment isn’t handled by the IRS, it’s a program under the Department of Labor and administered by the States and federal agencies notoriously don’t talk to each other.

There’s also nothing wrong with just giving them unemployment benefits, but you structure your tax system so that the rich people, when they end up needing to claim unemployment, are paying more or equivalent in taxes paying into unemployment than they’re getting in the payout. You simplify both sets of laws, the IRS is in charge of collecting revenue and the subdepartment of Labor tasked with this only has to worry about dishing out your cash so the administration of the benefit is simplified, and you still get your desired result of exceedingly well off people not “dragging” the system