This is about finances. If the US declares you a terrorist organization, you cannot do any banking anymore, even outside the US, since most banks do not want to gamble on SWIFT access.

Since the US considers anything "antifa" as terrorism now, it already had most concerning distant effects last year. See GLS bank cancelling Rote Hilfe in Germany. 1933 was the last time Rote Hilfe was cancelled, btw. It's an antifa OG. Pretty good indicator about the status quo..

Anyway, look at e.g. GrapheneOS, which is already treated as probable cause by law enforcement. Encrypted messaging also super sus. Thing is, funding can't escape jurisdictions. Signal servers are not running on love and fellowship, but donations and public money. Opsec won't protect your software stack's foundation against US finance attacks.