I know this has been requested before, but trying again :)
I’ve only owned my Arc (+sub +surrounds) for a week, but I’ve already had a couple of times where the TV cannot see the Arc via HDMI-ARC so I get no sound. Having used other HDMI-ARC connected sound systems, this seems to just be a fact of life and I don’t think there is anything specifically wrong with my Sonos gear or set up.
A good old ‘turn it off and on again’ is all that is required to fix it, but that is unfortunately an utter nightmare as the Arc power plug is buried away where it is very hard to get to.
Please, please, please can we have a reboot device/system function in the controller app. Or even a key combination on the unit itself to get it to reboot. Apple provide the ability to reboot Homepods from the Home app and it is very useful.