The RMD is the amount you are required to take based on the previous year’s ending balance (so 2023 balance). No it is not after the tax withholding was taken out. The gross amount in box 1 is the actual amount that was taken out of the account. Whether you got it or some went to withholding. The withholding was for you.
See IRS publication 590-B for IRA Distributions
https://www.irs.gov/pub/irs-pdf/p590b.pdf
