Five Eyes country are subject to local data disclosure orders and gag clauses, forcing them to hand over user data that may then enter the shared intelligence pool

There are no Five Eyes country in the EU.

the company is based in Australia, which is part of FVEY

Is fastmail not australian?

No, but there are nine eyes and fourteen eyes with EU countries.

they offer services in the EU

Not sure Five Eyes will outlast Trump, the UK has reportedly stopped sharing some intelligence with the US:

https://www.courthousenews.com/uk-faces-questions-on-complic...