@SimonSt
If you already have the Roku Express 4k (3940) which comes with the Simple Remote with no TV or volume controls, you can upgrade to the Roku Voice Remote. https://www.roku.com/products/accessories/roku-voice-remote
You can also find the Voice Remote at Walmart, Best Buy, Target, etc for about $20.
The other option is to purchase a Universal Streaming Remote that is compatible with Roku devices. (these are IR based -- line of sight). Again, you can find these at Walmart, Best Buy, Target, etc for $10-20.
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If you don't currently have the Express 4k (3940), perhaps consider purchasing the Express4k+ (3941) that comes with the Voice Remote if budget allows.
Roku Community Streaming Expert
Just another Roku user... I am not a Roku employee.
Insignia RokuTV, Ultra 4660, Premiere+ 3921, Express 4k+ 3941, Streambar 9102