Not sure how common it is now, but based on repair manuals my TV's wifi is provided by a standard m.2 wifi module and can be trivially removed. That wouldn't stop them from changing the TV's OS to nag or otherwise disable itself afterwards but the hardware change is about as trivial as it could be.
Now why the disable wifi option isn't available on the TV when it appears in the user manual is another matter...
>Not sure how common it is now, but based on repair manuals my TV's wifi is provided by a standard m.2 wifi module and can be trivially removed
Or just do egress filtering[0] on your router and block the device from communicating with the Internet. No disassembly required.
I block all access to/from my "smart" TV at my firewall/router and it works just fine.
[0] https://en.wikipedia.org/wiki/Egress_filtering