I also had to take this approach with my LG TV. The OS actually had its use for a while but Apple TV has become my driver. I no longer wish to consent to LG’s EULAs which are starting to look like the legal corpus of a small nation. I’m also not interested in their software updates. Internet privileges: revoked.
It’s concerning nonetheless as others are pointing out that in the current trajectory the TVs may soon refuse to display any content unless connected.
I’ve read reports of these devices turning on wifi and auto connecting to known public wifi networks. Seems we went from a generation of technologists dismissing Stallman as paranoid to one living in his nightmare and not being appropriately familiar with his work, issues of art vs artist aside.
It's simple: not buying them is the way. There is enough competition to just buy a screen that will not do that.
LG TVs may be rooted. You probably can also run a pi-hole sort of thing to block any traffic except whitelisted domains.
Not that I've done it, I don't get enough value out of it to justify the hassle or the privacy intrusion.