Using Sonos Beam w Apple TV - permanent audio output

I have the Sonos Beam HDMI cable plugged into the HDMI ARC input on the TV. Then the Apple TV HDMI just plugged into another HDMI port on the TV. I have selected "Receiver speakers" on the Apple TV Audio Output panel. It plays thru the desired speakers, but I can not control the volume with the Apple Remote. (I also have a Sonos AMP hooked up with two wall-mounted Sonos speakers... I can choose them, but have to do so each time ..., too.)

I am going thru the steps you shared above. However, I realized I was not absolutely clear. When I choose the “Reciever Speakers,” i can not control the volume with the Apple TV Remote. BUT …. If I go down the list of speakers available and choose “TV” — which is what I named my Beam when I set it up to work as home theater sound bar, I can control the volume with the Apple TV remote. I went to remote set up and put it on TV via IR … some results. I could then see the TV + - audio symbols, and they blinked, but did not affect sound volume. When set as in the pic below … I can control volume with Apple TV remote …and the + - column symbols are those of the Apple TV.

I now have the LG TV remote set for HDMI-CEC … and i can’t mute the audio, but I can seem to control the volume within a band set when i selected the beam and the surround sound speakers. However .. what does work, is to use the Sonos app to control volume …. So maybe that’s the way to go … even mute works.