To authorize repelling a slowly gathering military coup? That's an incredibly low bar to commit treason, since honestly, even at the highest levels military bureaucrats aren't going to be much wealthier than 10 mil. Unlike Congress, there's a much closer eye kept on the finances of military leaders because they're paranoid about foreign nations bribing them. It's physical national security, which is one of the few areas that money doesn't hold absolute power.

Even if they stood to lose a few million, there are plenty of genuine patriots, as well as people smart enough to realize that overthrowing the government by force does not mean the law instigating it gets repealed, but that the entire legal structure of the United States is no longer functioning. That's fifty different militias reporting to states, Naval, Army, and Marine branches with hundreds of billions of dollars in ordinance that's explicitly empowered to not follow unethical or illegal orders. It'd be a disaster for the coup throwers unless they managed a movie villain level simultaneous takeover of the Pentagon.

I'm not saying a coup is impossible, but the idea of rich people successfully overthrowing the American government by "hiring an army" is so cursed to failure that I almost don't know where to even start. Could they cause unprecedented chaos and potentially kill a large portion of the government? Possibly. Could they succeed? Absolutely not.

Also, this whole chain completely ignores the fact that Congress would never set the cap at 10 million. I doubt they'd set it at a hundred million. My bet would be one billion, where it wouldn't actually affect any of them. Were they to actually pass a 10 million dollar cap, the world would be such a different place that we wouldn't need to worry about a handful of grumpy generals inciting treason.