Greetings sussybuskets,
It sounds like you are having intermittent sound loss with your Apple TV 4K. We know how important having a working Apple TV is for you, and we will help get you to the right place to find a resolution. The first step is to calibrate the audio following these steps. This simple action can often resolve these types of issues.
If your Apple TV is connected to a home theater receiver or TV using an HDMI cable, you may experience audio latency, a delay that sounds like an echo when playing audio on both receiver speakers and a wireless speaker.
You can use an iPhone to calibrate the audio signal on your Apple TV so that all speakers play in sync.
1. Open Settings on Apple TV.
2. Go to Video and Audio, then scroll down to Calibration.
3. Select Wireless Audio Sync, then follow the onscreen instructions for using your iPhone to sync your speakers.
For more information, see Adjust video and audio settings on Apple TV.
This information is located in the Apple TV User Guide:
• Use Apple TV to play audio throughout your home - Apple Support
Cheers!