As others have said, cut off access and/or factory reset it.
My LG has never been granted net access, firmware upgrades through USB drives, and streaming through Onn 4K box(w/ a 3rd party launcher) and Apple TV. No surprise ads, apps, or anything.
Typically not all that relevant most of the time to the average consumer, but if you’re having a persistent annoyance it’s worth looking through release notes from time to time.
This ignores that the vast majority of consumers actually use the smart tv features like the Netflix app. Then updates start to become far more relevant and eventually mandatory.