Earlier quoted context omitted.
They do have a universal search but some of the big players like Netflix don't support it which meant that when I had an Apple TV I never really used it. The interface isn't that consistent either because app developers can pretty much do what they want so Netflix, YouTube etc. have the same UI they have other platforms for the most part which is different from Apple's. Of course Apple does the same thing and the App…
It is pretty much only Netflix that does not want to play ball. https://support.apple.com/en-us/HT208083
It's much patchier elsewhere.