The problem isn’t so much dependence on software from non-EU sources as it is dependence on software from profit seeking companies that, in order to maximise their profits, do all they can to lock in users and avoid interoperability and data portability. Also, to maximise profits, they are inclined to collect and sell data from and about their customers that are not essential to the software or interests of their customers. Open source software mitigates some of these problems and it doesn’t mater where the developers reside. Dependence on services provided by non-EU companies and/or hosted outside the EU entails problems but many of those are independent of the software and where it originates. They are inherent in the entities providing the service existing in non-EU jurisdictions and being subject to control by non-EU interests.