alt Hacker News>Google's Android is the largest OS by usage.
I am primarily thinking about government institutions and corporations. There Microsoft is used almost everywhere.
Mobile phones are a secondary issue in my opinion, also because Android is already much more open than Windows.
There's an attempt to move away from Microsoft enterprise tools, e.g. 365+ ecosystem.
See opendesk.eu , it's a platform collaborating with many EU open-source developers, and it's funded primarily by the German government.