There a few options. One is to simply disconnect the tv from the internet by a) disconnecting from you your network via the tv, or b) using your router to enable or block the tv internet access whenever you want to. c) use your router to restrict the tv bandwidth via Quality of Service settings.
I recently bought an LG tv and as soon as it connected it started flooding me material I didn't want. So I disabled the TV's internet access in the router, but still keep the tv connected to my wifi network.
If I need to stream material I can simply enable internet access for the period that I need. However I find it easier to use a laptop and chromecast connected to the tv. I then cast from the laptop to the chromecast via the wifi network. In this situation the TV is "permanently" blocked from the internet but this setup still allows streaming via the wifi network to the tv.