based on Steam Achievements, assuming the majority of the 800,000 got off the Nautilloid, but less than 1% have that achievement, we can assume that vastly more people own the game than 800,000. My most conservative estimate would be concurrent players represent 10% of BG3’s playerbase, so sales likely exceed 8 million.
Aren't achievements bugged right now? All of mine say that 0.1% of players have them. I wouldn't extrapolate based on achievement numbers until that's fixed.