MEDIA CORE 8KTVFire OS and Vega OS need separate compatibility checks and release packages.
These store steps apply after this platform release has been approved and published. There is no current installer for this platform.
Identify your Fire TV model and operating system. The Android APK is not a Vega OS package.
When the matching Fire TV release is available, open Find → Search on the Fire TV home screen.
Search Media Core 8KTV and open the verified listing linked here.
Choose Get or Download, then launch the app.
Connect the on-screen code with your lifetime account.
Use the official Amazon Appstore listing linked from this site. Do not use an Android APK for a different operating system.