Ok so the 40% rate comes only from federal income tax, which is heavily biased towards poor people paying less compared to other taxes such as social security, sales tax, and property taxes.

Income tax was 53% of the federal revenue in 2022 (https://www.taxpolicycenter.org/statistics/percentage-revenue-source) while social security is 30%, and the latter cannot be avoided if you are poor as they still take it out of your paycheck. So already we're off to a bad start on "The 1% pay 40%", as it's 40% of 53% of federal income which doesn't even include state taxes.

Total federal income from taxes was $3.4 trillion in 2020. Total state and local income from taxes was $1.9 trillion in 2020. Of that 1.9 trillion, the majority (67%) was sales and property taxes (https://www2.census.gov/programs-surveys/gov-finances/tables/2020/2020_alfin_summary_brief.pdf), two types of taxes which hit poor people disproportionately compared to the rich (https://itep.org/whopays/).