Plexamp is a good option if you already have a Plex setup and subscription. I also use it and like it quite a bit. But it's paid only, and doesn't seem quite like what the author is looking for in terms of UI and focus.

Another option is something like MPD, there are some nice graphical clients for macOS and it has good flac/cue support (a single file album shows up as individual tracks in the interface), but you have to set up the mpd server first, then choose a client, and it can be a pretty DIY experience. I use a setup like this on linux but have never set up mpd on a mac.