Can't control HomePod Mini with keyboard volume buttons in iTunes

Hey BKcooper,

Are you able to use the volume slider in the Music app to control the volume? Take a look at the section "Use AirPlay to control HomePod" for those details: Use HomePod with Music on Mac - Apple Support

Use AirPlay to control HomePod

If your HomePod is streaming music directly from Apple Music, you can control its playback—change the volume, shuffle or repeat songs, or add or remove songs from the Playing Next queue—in the Music window.

1. Play some music on your HomePod.

2. In the Music app  on your Mac, click the AirPlay button  at the top of the Music window, then choose a HomePod listed below “Switch to.”

3. Do any of the following:

• Change the volume: Use the volume slider at the top of the Music window. The maximum volume is limited by the HomePod volume setting.

• Shuffle or repeat songs: Click the Shuffle button  to turn shuffle on or off or click the Repeat button  to repeat the songs.

• View the Playing Next queue: Click the Playing Next button  in the top-right corner of the Music window to view the queue. See Use the Playing Next queue.

You can control only one device at a time; when you want to control your computer again, just switch back to it.

Thanks for using Apple Support Communities.

Take care!