Where the OP has (my emphasis):
...Example: I have several font files sorted 1 or more font files in 1 matching dir. All are sorted by (sub) categories and sorted by (sub) alfabet. All have different names. I need to get all files from all subfolders into the main folder.
D:\Fonts\misc\categories\alfabet\ > D:\Fonts\ ...
I could be wrong, of course, but I'm having difficulty seeing a driving need for this obsolete Windows File Explorer single-function add-on to continue, given that it has been superseded by the ability to flatten folders to one's heart's desire in modern Windows File Explorer
alternatives - e,g. xplorer²
(which I have used for ages), or XYplorer
suggests) - i.e., the problem has kinda "gone away".
I suppose the presumption here is based on my experience that, for years, probably no-one needing more complex file management would necessarily be able to rely on using Windows File Explorer for it anyway.