I think Microsoft has finally realized that its animus toward projects like Wine and pre-acquisition Mono was ultimately unproductive, and a net negative for Microsoft itself.
I still don't trust MS's motives in general, but I think they at least recognize that Wine/Proton helps make the Win32 and DirectX APIs a sort of de-facto cross-platform standard when it comes to things like desktop gaming, and that this is a good thing for them.
On the server side, MS knows that Linux is by far the most popular server OS, and official support for running .NET backend apps on Linux from MS themselves is a win for them as well.
I still don't trust MS's motives in general, but I think they at least recognize that Wine/Proton helps make the Win32 and DirectX APIs a sort of de-facto cross-platform standard when it comes to things like desktop gaming, and that this is a good thing for them.
On the server side, MS knows that Linux is by far the most popular server OS, and official support for running .NET backend apps on Linux from MS themselves is a win for them as well.