Disconnecting it from the internet isn't enough, because it will store spying data forever until it gets a connection, and it will connect to any open WiFi. You have to disconnect it from the power, and then use a sledgehammer on the remains.
I'd rather open it up and remove/destroy just the network card.
(I don't have to do so though because my tv is 20 years old.)
If that happened would any of that data get tied back to you? If you haven't created any accounts or signed into anything.
>and it will connect to any open WiFi
I've seen this claim made over and over again for various smart TVs, but so far I haven't seen any concrete evidence of this, only random speculation.