He's made billions in just crypto schemes. Then the bribes to pardon people. It just gles on and on. He never provided evidence that he didn't accept the salary, just said he donated it to federal agencies, which you cannot even do.
Note that in addition to specific programs that accept donations, this list includes "Gifts to the U.S. Government" with no strings attached and "Gifts to Reduce the Public Debt".
I'm sure he exaggerates his wealth, but we know he's at least a billionaire.