He's also basically shorting S&P and Nasdaq ETFs - $1.8billion is a blip against these, like throwing a pebble at an oil tanker...yet the article seems to have an air about it like the very presence of this man and this money is enough to help precipitate his expected downturn.
The market does seem overpriced at the moment, particularly stocks like Nvidia undergoing some kind of correction, but it seems that the medium term trajectory is on the rise. I'm not sure what kind of huge downturn the market isn't going to be able to account for when phenomenal, unprecedented shocks like COVID are something it took in its stride even though prices are still recovering due to the debt so many companies took on. The bullish run of the past 6 months seems to have taken analysts by surprise so to be expected that some of them are now betting against its turn in the other direction.