Hello @fcr1 and thanks for the question! I'm happy to help.
If I understand your question, you want to know if there would be a tax benefit in converting your 401k, and other retirement accounts, to a Roth IRA.
Contributions to your 401k, as well as some other retirement accounts, are normally made on a tax deferred basis... meaning that there was no tax paid at the time it was contributed and it will be "taxable" when distributed. Contributions to a Roth do not avoid tax when contributed, and are therefore generally non-taxable when distributed.
However, when moving money from a tax-deferred account to a Roth account, the entire "conversion" is taxable in the year that it is converted.
The tax that would result from converting the money to a Roth, in this particular situation, would be greater than the tax that would result from withdrawing the money over many years.
Another aspect that you may be considering, is the affect on the amount of Social Security benefits that you may be eligible for. Retirement benefits are not considered "earned" income and are not considered in the calculation for reducing Social Security benefits.
I hope that I have answered your question. There are many factors that can play into this decision.
Reach out if you have any additional questions.