Samsung Tv's have Roku CH app, in which case you use the tv remote navigate and not on-screen arrows.
You mentioned a Roku 4K+, if you have this attached to your Samsung tv, then you would go to hdmi input the Roku is attached to, and switch to the Roku remote. The samsung tv remote cannot navigate Roku 4k+ home screen or within any channels on the roku 4k+. What 4k+ do you have? A stick 4k+ or Express 4k+? The stick can only be controlled by wifi roku remote. Where the Express 4K+ can be controlled by an aftermarket IR remote, or an oem remote like the Samsung tv remote that actually has Roku code programmed in.
Edmund
Roku Community Streaming Expert
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