There is no reality in which she had a 50% stake in hinge at the time of sale. I would be shocked if she had >1%. She was involved only in the very early stages.
True, though the stock market has gone up a ton since 2018. If she put $50M into a mix of tech stocks, crypto, and Bay Area real estate in 2018, she could have hundreds of millions by now. I agree she likely doesn't have a billion if the Hinge sale is the primary source of her wealth.