>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