Liquidate 401K - how to max returns post-BBB

My widowed mother inherited a $1M 401K from my father and wants to withdraw all of it. She makes about $70K from Social Security and a RMD comes out to around $40,000 (after withholding, it's about $70K gross). She also earns $45K in dividends per year.

It has been 2 years since my father passed and she did not take advantage of the surviving spouse benefit, and insisted on merely withdrawing the RMD. Of course, she changed her mind in the year after the benefit no longer applies.

So total taxable income, counting the RMD is around $185,000/year. This is just a hair below the $197,300 that kicks her up into the 32% tax bracket. She doesn't want to pay 32% taxes and is afraid the RMD will force her up there very soon. So my strategy is to liquidate the 401K and reinvest it, where she can sit comfortably at 24% on passives without being forced to declare an additional >$70K income.

What's the best strategy for doing this, maxing out the 32% bracket over a 5 year period, the 35% bracket over a 3 year period, the 37% over a 1 year period? Are there any ways to declare a massive enough loss to balance against the income from a liquidated 401K?