Yes! My IR simple roku remote adjust my Sonos sound bar for the TV. Do you have to go into the Sonos app and under their settings so the Sonos sound bar can learn the Roku remote. Settings, then add remote, and it will walk you through the rest in the Sonos app.
I have the same issue. I have other non-Roku TVs set up with Roky streaming devices. For example: my 4k Streaming stick is plug is connected to a very old Samsung, and the Roku Remote will both turn on the TV and control the value by IR.
For the Roku Brand TV I spent time with support, they were pretty clueless. It apears from what they got from other support personal and there printed help, the Roku Brand TVs specifically turn off the IR on the paired remote so that you must use Roku soundbar, unless the soundbar can connect via CEC (which optical does not support).
The same situation of IR works with my Ultra box connected tio a new Sony TV.
I am going to see if switch remotes will Hhelp.
I believe I had the same issue. I found it under settings (maybe remotes?) in Sonos settings under that soundbar. Try that. Then make sure your tv has paired w your Roku remote as well.
You need to sync your Roku remote with the soundbar through the Sonos app.
Open the app and select Settings/System. Then choose the sonos device you are syncing. Scroll down to “remote control setup” and follow the instructions.
Just go into your Sonos app, click on settings -> system. Click on the room your playbar is in. Then scroll down to remote control setup. Follow the prompts and you should be all set.