The German federal government alone will pay 1.28 billion Euros to Microsoft until 2025 [1] so I’m pretty sure they do care about their government contracts.
[1] https://amp.zdf.de/nachrichten/politik/deutschland/it-open-s...
[1] https://amp.zdf.de/nachrichten/politik/deutschland/it-open-s...
There are Microsoft stuff that now are Linux only, like SQL Server containers, the Windows variant of them is no longer supported.
By the way several NRW libraries use custom Linux distributions.