No, it can not. When a wifi roku remote is paired to a Roku tv it control everything by wifi including volume and power. If you have non-roku soundbar the roku remote woulds never control it directly, roku remotes only control tv's. It is upto the tv via hdmi-cec to control your sound bar. Refresh the CEC devices in the roku tv settings> system> control other devices (CEC)> search for cec devices> follow prompts.
So the roku controls the roku tv by wifi, and then the tv controls the soundbar by hdmi-cec sent over the hdmi cable.
Edmund Roku Community Streaming Expert
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