Italy does the same: https://github.com/pagopa/io-app This is the official government app (you can get benefits, pay taxes, etc...), downloaded by 30+ million citizens, stack is React Native + Typescript
maybe EU countries could save a bundle and co-develop these apps. might also improve quality / ensure best practises are available to all etc.
This is not for co-develop. This is mainly report, of what government done. For some extent it could be used to check safety of software/infrastructure.
For example, in Ukraine used closed source software, and only war (because censorship), slightly slowed stream of scandal publications about bugs and vulnerabilities.