mpv tries to be pretty minimalist (and does this well), you could try a frontend (Celluloid, Haruna, etc.). And for the commandline, when you install the mpv package, depending on the distro, the package creates a default shortcut/desktop file, so you can open videos on your WM without hitches, on the menu bar. You can associate the shortcut to mime/file types and set as default player too. You can create yourself a desktop file too if necessary on your profile (eg: $HOME/.local/share/applications/mpv.desktop) with this file/content [1]

[1]: https://github.com/mpv-player/mpv/blob/master/etc/mpv.deskto...