The app is not on the Play Store: you install the APK file yourself. It is safe, and the same method is used for updates.
Tap Download. The file is about 37 MB.
Android asks for permission to install an app from outside the Play Store. Accept it for the browser or file manager that asks: the permission only applies to that app.
Tap the downloaded file, then “Install”. If Google Play Protect shows “Unknown app”, choose Install without scanning.
Pick your language and your source on first launch. Everything can be changed later in Settings.
From the TV's Play Store, install Downloader. That is what fetches the file.
In Downloader, type the code 3721658, then install the downloaded file. The TV asks once to allow the install: accept.
Sign in with the same Google account as on your phone: your watched episodes and current playback arrive on their own.
The app has a “Report a problem” button in Settings › Account: it prepares an email with the app log, which is what makes a failure understandable. You can also write to animelover.app@gmail.com.