So I have two Google accounts, I want to have one in the Google TV home menu, so I can see recommendations and all that stuff.
Then I have another account in which I pay YouTube premium, so obviously I want it to be the main YouTube account and I don't want to switch account every time I open YouTube.
Is there any way?
On your YouTube account (in a browser), create a separate channel.
Then, on the android tv sign out and clear data for the YouTube app. When you sign back in, it will ask which "account" to use (and you pick from the list of channels).
I'm using this to stop my family from flooding my personal YouTube account with Cartoons, Blippy, and Disney travel tips videos.