Okay. Did a little reading and found out there is a little modding that needs to be done now to make the Xfinity app work for certain Android TV versions. There’s even a different version for Fire TV devices. Anyway, if you wanna try this one for your Onn box, here’s the download link: https://tinyurl.com/xfin7416
And if the icon doesn’t appear up on your homescreen after installing, here’s the companion apk to install afterwards, very small (under 1MB). It makes the Xfinity icon show up and launch from homescreen. https://tinyurl.com/xfinicon
Here’s also the Fire TV version. Some people report this works for them on devices other than Firesticks. This is the mod of the 7.3 version. Can give it a try as well: https://tinyurl.com/xsfire7309
And here’s the homescreen shortcut icon for that one: https://tinyurl.com/ftvicon