Version: 0.38.0 Web: https://mpv.io
While Mpv is a CLI-based player, it does ship with a GUI interface of sorts. You can bring it up with flatpak run io.mpv. Mpv --playeroperationmode= pseudo-gui .
VLC is the catch-all media player on Linux. It can do a lot of things, but you wouldn’t call it lightweight. If you want to use a minimalist media player, and aren’t averse to the CLI, you’ll want to use Mpv.