I don't know about that - seems like US is close to half of Tiktok revenue: "TikTok took in an estimated $10 billion in revenue in the United States last year, he said, out of a total global revenue estimated at $20 billion to $26 billion." [1]
US market isn't likely to grow much going forward though, while developing countries have a lot of growth potential. Meanwhile, TikTok is bringing in at least 10bln annually already. Pure profit isn't the only thing that makes it valuable though, it's one of the few global media platforms that's not owned by the US.