That is because aTV 4 does not support HDMI-CEC.
False, the aTV 4 does support HDMI-CEC.
IF HDMI control doesn't work, the problem is that your television isn't listening for it.
and changing to a aTV 4k won't fix that.
You may need to enable HDMI-CEC in your television's settings
different manufacturers call it different things (LG=simplnet, Samsung=Anynet+)
check here for full list -
https://en.wikipedia.org/wiki/Consumer_Electronics_Control
info from apple on this -
https://support.apple.com/en-us/HT205225
I still can't fathom out what the side arrows are in the volume icon in settings
side arrows?
which settings are you in? app on phone, settings on aTV? be very specific how you got there.
also you mention the "select icon", I'm not sure what you're talking about.
if you have the older apple remote with the circle buttons, either silver or white in color, then you might not have an aTV4 or 4k, the remote that comes with the 4 & 4k is black
(the silver and white will still control a 4/4k but you don't have volume controls or Siri)