Depends on whether or not Cyberpunk gets ported to toasters, potatoes, and smart cars.
It might go on streaming services, how do you track that? Unless they're all like google stadia and you still have to buy the game.
Standard high fantasy is way more popular than anything sci-fi. Can it sell more than Fallout 4, probably not.
Fallout 4 sold some 15 million units. Deus Ex games don't even pass the 5 million. Mass Effect games are under 5 million, yet for some reason people expect this to beat 30 million? Witcher 3 sold some 20 million copies. So I'm guessing 10 million as sci-fi is half or less as popular as fantasy.