Earlier quoted context omitted.
Where are these smart folders in native Windows? The closest I see is a “saved searched” and this is really more obtuse than creating a playlist.
Windows 10 calls them Libraries. Open your explorer and it's in the left sidebar. You can create new ones to group files and folders together regardless of where they physically reside. They are already used by Windows to provide the major Documents, Music, Pictures, Videos, etc. locations.
https://windowsreport.com/enable-libraries-windows-10-file-e...
And another how to article.
https://windowsreport.com/enable-libraries-windows-10-file-e...
This is why geeks end up designing Homermobile type solutions and wonder why the common person is confused.