Google provides only for official development hardware like:
This is the closest you’ll get to a “generic” Android TV 12 environment. android tv 12 iso download link
For testing and development, you can download factory images for the hardware or use an emulator: Google provides only for official development hardware like:
Downloading a standalone Android TV 12 ISO for general PC installation is primarily possible through community-driven projects like AndroidTV-x86_64 android tv 12 iso download link