We should remember that interest rates are lowered by giving money to the wealthy people. Unless, of course, the central bank is purchasing long duration bonds from the government, and then we don't know until when or if those bonds are rolled over. I don't know how to calculate the total amount of money given if there is both going on at the same time.
Low interest rates also create a much larger spread between the market price of your asset and the value of your asset during any type of Correction. This will disproportionately hurt poor people, obviously. If I borrowed to increase my farm output, and prices drop, then someone richer than me can borrow at a lower interest rate to scoop up my assets. The higher volatility hurts me. Especially if some of the low interest rate is being maintained because regulations force pension plans to purchase a certain percentage of government bonds
So much of all this depends on how those deficit dollars are being spent. I don't think you can just look at the natural interest rate to make that determination.