Nope. For that to work, Plex would have to publish the content of any server/library to those respective platforms. Amazon, Netflix and Apple media are found, because they do so for their respective catalogs – the same should go for the US plex video-on-demand catalog.
The search you’re using for those platforms aren’t local.
Good points.
But wouldn’t it be nice if we could use the voice search on the remote (either Fire TV 4K Max or Apple TV 4k) when we are in the Plex app’s search window…