Linux is commonly used in the communications systems, like on invidual radio “stations”. Propably used everywhere where high confidentiality and security is required.

Nope, unless you are worried about stalkers.

Real shame that GrapheneOS only supports google pixels since they are kinda expensive.

They never happened. Winners write history.

I’m not a fan of idea of completely getting cut out from parts of the fediverse because of ideological differences. Imo that just promotes further polarization. Though I might look into blocking couple instances if and when I get annoyed enough lol