Cannot get any volume-related commands to work with media_player (Google Chromecast with Google TV)

I have a Google Chromecast with Google TV hooked to my TV. I have added it via the Android TV remote and via the Google Cast integrations. I can play/pause/change destinations perfectly. When it comes to any volume (volume up, down, mute), it simply ignores me. Even in the states area, it always shows “is_volume_muted: false” which is not true–I have it muted right now. I have restarted HA, the whole TV system, the Chromecast with no luck. It just ignores the volume of this device alltogether.

I’m about to give up here.

I had similar issue and couldn’t get volume to work at all. I did find a way to get it to work in my case.

On the Chromecast
Settings > Remotes and accessories > Set up remote buttons > Volume Control
This was set to TV (IR) and I changed this to Auto (CEC) and now it works. Setting it to Chromecast also worked but I’m using HDMI-CEC with my soundbar so left it on CEC.