TikTok's main user base is the USA. If TikTok sells their US app, they can't support themselves on the rest of the world. TikTok isn't even the leader in China.
US Meta can definitely support itself at it's current size without EU Meta.
The company scaled to support the world’s largest economy.
Remove that. Recognize they can’t compete in #2 (China).
Then how can you justify their current scale?
What do you mean by more popular than any meta or us app? WhatsApp has 2b monthly active users, where as TikTok has little more than 1b.
More important than user count is user economic purchasing power.
Are there any numbers for that? I highly doubt tiktok is doomed to fail just because is banning it.
It's still way more popular than any Meta or US app for that matter, is right now.