A couple of decades ago I saw a proposal for a national VAT structured in a way that would not be "overly onerous" (their words) on low income earners and the lower middle class. I included a complete elimination of the IRS and federal income taxes and had several exemptions from the national VAT;
All food items except what they referred to as elite items such as lobster, caviar, truffles, premium grade meats (anything above USDA Prime such as Wagyu).
All heating/cooling fuels for residential properties.
Automobiles with a MSRP higher than the US median price (currently $50k).
Gasoline and diesel fuel (except for existing federal taxes)
All clothing/shoes priced more than $150 (they put the cutoff at $75...I adjusted).
Those are the standout items they exempted. There were others that they considered essential for everyday life of the average person. While an average family would be able to purchase a decent pair of something like basketball shoes for a kid without paying a national VAT, all the cost of shoes like Gucci, Christian Louboutin, Jimmy Choo, etc. would be taxed. For families where mass transit is not available, a basic vehicle would be exempt but the BMW, Mercedes, Bugatti, etc. would be taxed. All recreational vehicles (ATV, watercraft, etc.) would be taxed.
A simple national VAT would be a disaster, but with careful thought and the proper structure it could work. People forget it would capture income paid in cash and illegal incomes because criminals spend money. It would, however, encourage barter as a way to get around the sales tax. Currently barter is not a material portion of the economy but a national VAT could change that. The problem with "selling" the idea to the voters is some (mostly liberals) would omit important parts and lie about the proposal to scare people.