Minimize Window in C++ With a Custom BP Node?

[Shadowriver]

First you need to get viewport, you can do so from GEngine:

UEngine::GameViewportForWorld

From here you can get slate window

UGameViewportClient::GetWindow

You can already minimize from SWindow, but you can go farther and access FGenericWindow, a native system window from this function

SWindow::GetNativeWindow

Note that in PIE you will minimize the editor it self, remember that editor also run on engine and running in PIE you actually operating editor it self