As this is the FIRST interactive title from Netflix it may take a while for Netflix to update the fetch app to support it.
Optus has NO control over this, Netflix must work with Fetch themself to provide an update.
Apparently, it's not yet supported on Chromecast or Apple TV, according to several sources online, support is limited to smart TVs, streaming media players, game consoles, iOS devices, and Android devices running the latest version of the Netflix app.
I'm sure there's a way you could potentially mirror the screen of a supported device or plug that directly into the TV to get the full experience. @MJH2
As @Paddylee has mentioned, it's a discussion that needs to take place between Fetch and Netflix.