Should you need it for later, here’s the first few steps after you have the Onn device (or an alternative Google TV device) in hand. The links included are guides for the steps.

For the VPN process (if you choose an Onn device), I remember having problems with the wireless hotspot method that led me to do the ethernet option instead, but either should work. If you choose to install LineageOS, I unfortunately don’t have experience doing that, but that would come before app installations.

If you are using an Onn 4K device, it should have a mappable star button that can only be configured while using the default launcher. I personally chose to map the TV’s input switch function to it, but this step should occur before setting Projectivy Launcher as the default.

Next, you would install the Downloader app via the Google Play Store. Not ideal to have to use the Google Play Store for any installation, but at least all subsequent apps can be install via Downloader instead.

Using Downloader, you can now install and configure Projectivy Launcher. This also involves installing the Launcher Manager helper app to configure the default launcher, giving you the option to return to the default if need be. While you can try uninstalling all the bloatware that comes with the device, some of it might come back with updates (though presumedly not an issue if you install LineageOS). Should that occur, you can instead disable the apps in the Android settings or hide them from the Projectivy Launcher menu. The hiding apps feature is also useful for hiding apps such as Downloader and Launcher Manager after setup, as they’re not regularly needed. Ensure you enable the override home button setting to make the button send you to Projectivy Launcher instead.

Stremio is available on Google Play again for now, but you can alternatively install it via Downloader too. SmartTube is of course not available on the Google Play Store, but can be easily installed via Downloader too. It has many configuration options for its UI and as an in-app self-updating function.

Alternatively to Downloader, you can also install a file manager app and install APK files manually. Devices like the Onn 4K Pro let you expand the device’s storage with a USB drive to transfer files or load external media, though apps such as atvTools (Android/iOS) let you send files wirelessly to the device’s internal storage.

While only the Google Play Store can automatically update apps, an alternative is the APK Updater app, which scans several APK sources to let you manually update installed apps. There now also seems to be a third-party F-Droid client for Google TV.

As the Onn 4K Pro has several sponsored buttons that become useless without their intended apps, I tried using a button remapping app to map newly-installed apps in their place, but had mixed results in terms of buttons acting up. People seem to recommend tvQuickActionsPro though, which might work.

An issue regarding SmartTube is that if you use the voice command functionality of the remote to look up YouTube videos, Google TV will try to open them in the default YouTube app. Normally, a bridge app could be used to connect SmartTube to the YouTube API calls. Since YouTube comes preinstalled on the Onn 4K Pro (though presumedly wouldn’t if you use LineageOS?), this method must be used instead. If you don’t use that functionality though, it may be a moot point.