You know nothing about taxes. The rate was reduced by Convicted Rapist Treason Trump from 34% to the current 20%. apple's tax rate the last 3 years, from their '22 10k:

from microsoft's '23 10k:

Tesls '23 10k:

Do go on about how the current tax is 20%.

now lets talk about the 15%- the biggest and most obvious loop hole is that it only applies to corporations that make more than 1 billion in earnings. Which, is actually relatively few. and if you can't think of a way around that for the few that are there, then you probably shouldn't be talking. I can think of a few ways. The easiest is to fork off functional sections into subsidiaries (which then pay their own taxes)

but under no circumstances did Biden do that without his corpo benefactors giving him the go ahead to do so in the first place. Because money is speech and corporations are people… and corporations have a helluvalotta "speech" to give. either to biden or his competitor.