If I open the CMakeLists.txt in tha attachment, accept the configuration for Visual Studio 2019 (I have the community version installed), then try to build, I get the output ("..snip" was edited) like:

Running ..snip\qt\Tools\CMake_64\bin\cmake.exe -S ..snip/AppData/Local/Temp/QtCreator-uWVRcU/qtc-cmake-qcIWrqnN "-GVisual Studio 16 2019" "-A<unsupported>" "-T<unsupported>" "-DCMAKE_BUILD_TYPE:String=Debug" ....snip
– Selecting Windows SDK version 10.0.18362.0 to target Windows 10.0.16299.

CMake Error at CMakeLists.txt:3 (project):
Failed to run MSBuild command:
..snip
error MSB4184: Der Ausdruck "[System.IO.Path]::Combine(obj\<unsupported>\Debug\, .NETFramework,Version=v4.0.AssemblyAttributes.cpp)" kann nicht ausgewertet werden.

It seems creator is calling cmake with invalid platform and toolset names
("-A<unsupported>" "-T<unsupported>" ).

Seems connected to
https://bugreports.qt.io/browse/QTCREATORBUG-24883