my andro tv is coocaa tv and whenever you are not pressing button on remote or playing media video it automatically play the google assistant video, "hi google what can you do, " bla bla bla, basically it shows how we can use google assistant. but when I connect via hdmi it showed up, not when like I play video, it really bothering, is there anyway I can disable it,
You can disable app goings to setting > apps > disable.
You can also use ADB to uninstall Google Assistant with this command:
A wile ago I wrote a guide to uninstall almost all system apps and change the launcher, if you're interested in that:
https://www.reddit.com/r/bravia/comments/czuo7q/guide_android_tv_debloat_and_customization/