Consumption taxes are inherently regressive. The lower your income, the higher the fraction of it that goes to consumption taxes. Wealthy people do not spend all their money buying taxable goods and services; they invest most of it in ways that avoid or reduce taxation. This is to be expected, somebody who makes 100 times minimum wage does not spend 100 times as much on food as a minimum wage earner, so the excess money can be invested in ways that reduce the taxes payable, compared to what consumption taxes would take.
If I had to get rid of one type of taxation, it would be consumption taxes, with the lost revenue being taken up by earnings taxes, including income, capital gains, and any other source of wealth increase, all taxed at the same marginal rates.