A lot of things have changed since Jio originally launched JioFiber and Jio Set top box. JioFiber plans have changed, Jio has started offering unlimited data-usage plans and so has changed Jio stb model variant and inherent os capabilities via software updates. With unlimited data usage plans, Jio stb has certainly become an attractive offering.
There are several ways to install apps, not available on Amazon app store, on your Amazon Fire TV Stick be it the regular version or 4k version. Some of those methods involve cumbersome typing of complex or shortened urls in one of the downloader/browser app on firetv stick. I sincerely hate that. The most convenient