Cute point scoring about Clinton's record of leaving a surplus at a time of world peace is unhelpful.
The fact that the US economy is continuing to generate jobs at a totally unexpected pace strongly suggests that Trump's tax cuts did the job they promised; it's clear that if the pandemic hadn't derailed the economy, it would have been storming along as a result of his economic policy. The point about stock buy backs is that they release the money stuck in companies with no clear investment opportunities to be reinvested, at a lower cost than would otherwise be the case, in companies that do have expansion plans. Yes, of course that's not the only reason; the appalling problem of the double taxation of company dividends versus bond payments makes financial engineering always a profitable prospect, while foolishly designed executive bonuses based merely on share price also encourage such things. But it's not simple.
Yes, Biden talks the talk on taxing the rich. However the ever expanding number of loopholes (think IRA) means that it is only the relatively little people and careless corporations that will actually pay more tax.
Note I'm no fan of Trump, and the prospect of his getting a second term is terrifying. But it's important to try to spot what is really going on, not just assume a politician is telling the truth for the first time ever. In having the choice of Biden or Trump, the USA is getting what it deserves - at least a bit of it.