Very customizable library-based music player designed for huge collections of music (tens of thousand files). With lots of handy features to navigate and use your collection, like album/artist lock, menus to choose songs from album/album from artist, enqueue songs with middle click.
Some of the main features:
The windows use a layout system that allows users to completely change the interface. You can use pre-defined layouts or create your own using text files that allows you to pick and choose the widgets you want, their options and their placement. These layouts can be used not only for the main window, but also for extra windows, the tray pop-up, or a desktop widget.
it does not work at all. you can install it normally, but when you try to open it, the programme dose not open. I’m using Mint 21.3 Cinnamon
Regarding the problem of unable to add folders to the music library: the default version delivered with Linux Mint is a flatpak bundle. This is the reason that it cannot browse the entire filesystem.
I think this is the best music library for linux. Unfortunately I couldn't add any folders to my library in this version. I currently use Linux Mint 21.1 Cinnamon. I downloaded version 1.1.99.1 with gtk3 from gmusicbrowser.org and it worked fine for me. I would recommend you to do so as well.