This article explains how to Change the icon in an Apple TV version.
* This requires a new build.
You can change the icon via Zapp:
1) Locate the desired Version of Apple TV in Zapp
2) Open the Dropdown Menu for this version, and Select "Configurations":
3) The Configurations Screen shall open:
i- Make sure you are in the "Assets" section (selected on the left-hand menu)
ii- Select the "App Icon" Tab
iii- Insert the 3 assets for the Small Icon, and 3 assets for the Large icon, according to the specifications on the page.
iv- Click on Save & Finish
v- You can now return to your Version in Zapp and Create a New Build (required for the changes to take effect).