The closest to what you desire is the old Plexamp 2.0 client for Raspberry Pi. Plexamp for Raspberry Pi Release Notes
But it won’t run on your hardware because it has been compiled for the ARM architecture.
If you have an Android device, you can use the regular Plex app on it. The Android TV version of Plex has recently learned to do sweet fades and loudness leveling. So you can use it as a “receiver” app for flinging music to it.
