Personally I've never liked using file managers. I have a folder on my hard drive called ebooks and within that I have first a folder called __Pending (the __ is so it will sort first) and following that I have a folder for each author, lastname, firstname.
In each author's folder I put all his books. If a book has 2 real authors I put it in each of their folders, although I don't have many books with two authors. I read novels amost exclusively.
In the __Pending folder I have any books that have to be checked and, if need be, fixed. Those are also in folders by author since I'll never catch up with that.
In addition I keep an ebook folder in Dropbox and also in OneDrive in which I put books I might want to read in the coming year. Actually that's where I usually select my next book but not always.
The problem with my system is too much redundancy. If I update a book I have to remember to update it in all those places. That's okay. I like the safety of that. I also back up the folder on my hard drive onto a thumb drive and I keep the last 4 backups. Lots and lots of redundancy. I'm only 76 years old so I have to work at making sure I have books for the coming century.
I do realize most people like to use some sort of manager. To me this is much simpler. It's not perfect but managers tend to be far less perfect. I don't care about tags and such or descriptions of the books. I remember most of them and I go through them from time to time reminding myself of the ones I've forgotten.
Barry