Hey Tikka300,
We understand you're having an issue with the volume level when using your Apple TV. We want to help with this. Have you checked the audio format, and tried using a different one to see if that helps? Those steps can be found under "Adjust other audio and video settings" here: https://support.apple.com/guide/tv/atvba773c3c9/tvos
You may also want to check the "Reduce loudness" feature. Those steps can be found in the same resource under the section "Watch Apple TV without disturbing others".
It's also a good idea to test while using a different HDMI cable, just to rule it out.
Keep us posted on the results.
Cheers!