I had an idea yesterday (09 May 2022, as I write this now) to write a calculator that would take an individual's AGI and some presumed gambling winnings and compute the amount of tax that would be owing on said winnings (and therefore what withholding amount would cause no change in the winner's eventual tax bill, because having to pay a gargantuan amount in taxes because of underwithholding is unpleasant).
DISCLAIMER: I am a mathematician, not a financial advisor. This page is simply doing some math. It should not be regarded as a substitute for actual financial advice. If you have a large amount of gambling winnings, good for you; please go find a financial planner and at least one lawyer.