I bought one of Samsung's smart televisions a couple years ago. I think I paid $1500 for it. Anyway, it started showing me ads and the TV eventually became sluggish less than a month after owning it. Returned it as defective. Ever since that experience, I swore of all smart televisions and will never buy another Samsung television or smartphone again if I can help it.
I never once touched any of the smart features and it has been fine so far. This has been my rule for any devices that requires WIFI. I should really setup a special guest network for them and disable WAN access but I haven't gotten that far yet.