Either billionaires really earn their pay, which implies that they are thousands of times more productive as a person than the rest of us - literally superheroes.
Or - if you accept this as the obvious bullshit that it is - then all that money is not a fair compensation for anything, but rather the consequence of being in a position of economic power that makes it possible to extract wealth from the economy in one way or another. How exactly said extraction is done is immaterial - if the wealth is unearned, it means that it was taken from someone else, since someone ultimately did the work necessary to create it.
You seem focused on the labor theory of value, and sidestep completely the entire idea of investors, or the entrepreneurial function they serve.
Advocate for higher taxes if you wish, but acknowledge that economics are not a zero-sum game and propose an alternative to savvy investment, unless you simply want to foment division or to upend modern capitalism entirely.