I recently went through most of the Spotify clients I could find on GitHub, looking for something "lean", including screen real estate.

Most of the GUI apps had something similar to the official app in the maximized window, but none had a good mini-player, something I could put in the corner of an external monitor and control most of the important functions with minimal mouse clicking, including EQ and playlist.

Interestingly this one with its Winamp mode is what I was looking for. Nostaliga is probably playing a part, but it a good UI does not have to be "modern".

I also went through a tour of TUI apps. Lots of interesting work there, but a full TUI with windows was less convenient to navigate, and some of them try to do too much. I wound up using https://github.com/hrkfdn/ncspot because it specifically does not attempt to be a character mode GUI. Almost like a ViMusic.