No, it covers EU citizens' data fully no matter where they are or where the data is. It may also cover non-EU citizens when in Europe which is perhaps what the article you read was referring to or had misunderstood.
It seems slightly unclear, but generally a lot of interpretations seem to be focusing on the location of the person. An American buying something in a European airport is protected by GDPR during their fleeting pass-through of the "GDPR zone".
https://www.hipaajournal.com/does-gdpr-apply-to-eu-citizens-... seems to suggest it is based on location. There would seem to be standing for anyone based in Europe that made an account when considering a move to the US, or who is based in Europe next Friday when the "data processing operation" occurs. That seems like it would give them standing, even if they weren't protected while overseas, as this is a new data processing operation.
