My set-up is a Beam and 2 Ones (w/Alexa) connected HDMI ARC (and tried CEC) to 2018 Vizio P series TV with Roku Premier + HDMI into TV. Vizio plays 5.1 on Beam set-up from built-in Vizio Prime and Netflix apps. Only get stereo output when playing Prime/Net Flix from the Roku. Spent a couple hours researching and trying different setting configurations. Made sure to power off and on so ARC could get a new hand shake, all firmware is up to date. If anyone has gotten Roku to pass 5.1 to the beam (through Vizo or other brand tv) please let me know your settings so I can try and duplicate.