The temporary files generated by qmake will be forced to be generated in the intermediate directory. You can check the local qt_private.props file located at C:\Users\{User}\AppData\Local\QtMsBuild.
To begin with, you need to modify the project settings for the intermediate directory. Then, edit the .vcxproj file to ensure that the <IntDir> node appears before the <Import Project="$(QtMsBuild)\Qt.props" /> line. For example:
<PropertyGroup Condition="'$(Configuration)|$(Platform)' == 'Debug|x64'">
<IntDir>_obj\$(Configuration)\</IntDir>
</PropertyGroup>
...
<ImportGroup Label="PropertySheets" Condition="'$(Configuration)|$(Platform)' == 'Debug|x64'">
<Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
<Import Project="$(QtMsBuild)\Qt.props" />
</ImportGroup>
<ImportGroup Label="PropertySheets" Condition="'$(Configuration)|$(Platform)' == 'Release|x64'">
<Import Project="$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props" Condition="exists('$(UserRootDir)\Microsoft.Cpp.$(Platform).user.props')" Label="LocalAppDataPlatform" />
<Import Project="$(QtMsBuild)\Qt.props" />
</ImportGroup>
or, Set QtVarsOutputDir before importing Qt.props, so the Condition in the qt_private.props file will be set to false.