This week-end I saw a post on the Matrix channel about a German company named Protelion. She proposes secure communication for governments with mobile phones based on GrapheneOS as stated in this PDF. Note the the solution more global and does not rely only on GrapheneOS security.
Today, the Cyber Security Council Germany excludes Protelion on "allegations of influence of Russian intelligence services" through her relations with the Russian Infotecs company, funded by an ex-KGB employee. The information comes from a German TV show: ZDF Magazin Royale. There is a blog post here and probably more in German but Ich spreche kein Deutsch.
Disclaimer: I do say that GrapheneOS is influenced by any Chinese's spy of the Russian FSB through a secret NSA program ... I have no idea of the relations between Protelion and GrapheneOS, if there are any relations. It is just that I saw 2 news about Protelion and in a short period of time, so I thought it could be of interest to the GrapheneOS community