I really need to remember the source because this seems to come up a lot. But Marx differentiated between proletarian workers whose labor power was used in production and other workers whose labor power was used in the redistribution of capital. For example, many finance capital workers are not proletarian. The terminology there may not be exactly right, but that’s the gist.
I think the whataboutisms that make class look murky are extremely rare. You’d need someone who both labors in production and owns the company and makes equal amounts from their wages and from their ownership. The capitalist class has long had a word for this type of person: a failure. I’d be happy to just call them petit bourgeois.