I just looked under the Streaming Store/Apps/Movies and TV and it indicated 499 available. Kids and Family 499. News and Weather 500. Animals and Pets 106.
I didn't check all the categories, but does seem to to populate past 100 for me. Anything already installed to the account has a white circle with a white checkmark in the tile icon.
This was on a US based Ultra 4660.
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More concerning to me is that Roku is inconsistent with its nomenclature/terminology. If you go to the online Roku Channel Store https://channelstore.roku.com/browse, still calling them "Channels". On the Roku devices, now calling them "Apps".
