Certainly Europe would be better off if they took this approach and banned all American apps. American techies have no respect for European privacy laws and will never faithfully follow the spirit of such laws, or even the letter.

They are smarter than a blanket ban, create rules that suite the EU, not just a blanket ban.

The biggest issue with this is also needing to adopt OSes and programming languages that aren't controlled by US companies.

I think the longer they wait, the worse it will hurt.

They're caught in a bramble bush and getting themselves unstuck is going to get them scratched up. But the longer they put off freeing themselves, the more the bramble grows around them. They should have done it years ago. They should do it now, before the "Trusted Computing" trap slams shut forever.

Being in the US, I don't think that would affect me too much, except for, of course, TikTok, which I don't have anyway.

Finally, this hypothetical would say "a recipient country may ban the app." It wouldn't say "shall ban the app." So your country can just decide to keep using whatever they like.