Nevermind on the Roku question - it looks like I wouln't need it, as I found in one of the reviews;
The H9G is an Android TV and as such offers a wealth of streaming apps, news and sports channels, entertainment channels, games, and more. Streaming video apps include Amazon Prime Video, Netflix, You Tube, Google Play Video, FandangoNOW, Tubi, 4K Now, and HBOMAX. You can also add Disney+, Hulu, Pandora, Pluto TV, and scores of lifestyle, sports, and music apps and games using the Google Play app store.
So I assume basically anything I can find on my phone I can get on the TV, which I am guessing would be Criterion and Kanopy as well.