He did not work multiple billions of dollars hard. No one can possibly work multiple billions of dollars hard. Bezos is worth 157 billion, and he's 59 years old, which averages to over $10 million per day since he was 18. Are you seriously suggesting that he has done 100 times more work, every single day of his life, than someone making $100,000 does in a whole year? Sure, he had some good ideas, and deserves to be fairly compensated, but that's monstrously out of proportion.

Capitalism does not, and has never, fundamentally rewarded hard work. Capitalism, fundamentally, rewards having a bunch of money to buy the rights to the value of the hard work of others. The most reliable way to get rich in capitalism isn't even to have great business ideas, it's to be born with rich parents so you can buy lots of shares in a company, and then use your shares to demand the company prioritize maximum dividends and minimum employee compensation. The investors that actually contribute meaningful ideas are a coincidential minority at best.

Sure, UBI and VAT are valuable ideas, but the main problem is that the robots will be owned by rich investors who made their money by being born rich enough to throw money at ventures that made them richer.

The actual solution is vesting the employees who actually create value with shares of the means of production they use to create that value. When the workers are the shareholders, they are actually compensated for their hard work, and the problem solves itself.