Go to this IRS Publication 915 and review the worksheets provided. There is no reference to earned income. It is taxable income as stated on the worksheet - Combine the amounts from Form 1040 or 1040-SR, lines 1z, 2b, 3b, 4b, 5b, 7, and 8
The Form 1040 Lines 4b and 5b is the taxable amount of an IRA or Pension distribution.
https://www.irs.gov/pub/irs-pdf/p915.pdf
