Apple TV and HomePods not working together as a stereo audio system

Part of what you said refers to only one HomePod or do you have two that are paired with each other and they became unpaired? HomePod pair not working? Or HomePod just not working with the Apple tv?

Begin with some Restarts:

• Restart the Homepod(s) - you can unplug for 10 seconds then plug back in, HomePod will display a white swirling light on top.
• Restart Apple TV - in settings- system - restart
• Restart/ Reboot your wifi modem - unplug for 30 seconds

All devices should be signed in with the Same Apple ID and connected to the same wifi network and all running the latest software.

Please review:

Set up a HomePod stereo pair - HomePod user guide - Apple Support

Use HomePod speakers with Apple TV 4K - HomePod user guide - Apple Support

Set up home theater audio with HomePod or HomePod mini and Apple TV 4K - Apple Support

If your speakers lost the stereo pairing somehow, then you may reconfigure that.

It doesn’t seem to be a widespread issue, else the forums would be flooded with similar posts.

It would help if you described better what exactly isn’t working so we can help narrow it down and suggest other troubleshooting steps. “It doesn’t work or is funky “ is too vague. The HomePods don’t come on or they go on and off? Or this is one homepod? Which model of HomePod is this? Is it with certain Apps? Etc.

if it’s cutting in and out it can be the wifi connection.

Since replying to you last there have been software updates released to all devices to update to 18.6. So do that.

Also since you last set up your Apple tv and signed into it , they might have changed how you sign out and sign back in to iCloud. This may require you redo these steps:

1. Go to Settings.
2. Select Users and Accounts.

• • For the default account, select your name, then choose Remove User from Apple TV.
  • For additional accounts, select your name, select iCloud, then choose Sign Out.

To sign back in you can use an iPhone or iPad and follow the onscreen instructions using your unlocked iPad or iPhone to sync your Apple ID.

I’m going to assume since you have an Apple TV 4K that you set it up for home theatre?

• In Apple TV: From the Home Screen on Apple TV, select Settings > Video and Audio > Audio Output. Select the HomePod or stereo pair that you want to use for home theater audio..