What do you use for Managing Collections?

I've been looking around for a Collections Manager (that is hopefully on Windows).

Here There were a few recommendation but none of them work for me for some reason.

This is another, but I would much rather use something that would allow me to throw books in different folders using Windows File Explorer (or something similar). Although, I don't actually get how I can easily customize Collections in Calibre itself and tags are too numerous.

Any help would be appreciated.