I would guess if anyone ever asks Warren to round up for charity, he says no. Billionaires mostly engage in philanthropy that furthers their own ideals: https://www.theguardian.com/society/2020/sep/08/how-philanthropy-benefits-the-super-rich

I'm glad you enjoyed the article, and would point you to this ProPublica link in the mentime, they did a great job of pointing out how the super-rich avoid taxes. In the meantime, don't let the top 20% off the hook. The ultra-rich don't live lives that look anything like yours. The rich top fifth, though? They live in your community and determine all your choices and they buy up starter houses as investments for themselves. It's bad for everyone.

https://www.propublica.org/article/the-secret-irs-files-trove-of-never-before-seen-records-reveal-how-the-wealthiest-avoid-income-tax