There’s a dozen apps for it, but I wouldn’t trust them to do a perfect job. At a bare minimum, you’d probably need to keep said app up to date at all times, and it’d need to be one that runs in the background or runs on every boot or something.
You mean Gabriel Knight?
I guess an AOSP-based rom, if one exists for your phone?
Reply to old reply, sorry. Technically blocking the IP isn’t perfect either. In theory, as long as it has the wifi credentials, and your wifi has access to the internet, your TV will be able to access the internet if it really wants to. All it’d have to do is ignore the IP assignment or fake/change a MAC address during DHCP. I don’t know why a “legit” TV would do this, but if you get some unbranded Chinese thing, or if any wifi device wants to be malicious, it can bypass DHCP+IP filters very easily.
Never connect your smart TV to the internet. Just don’t do it. Get a third party device or ideally use an old PC with an appropriate HTPC Linux distro or something.
I’d go for Jellyfin over Plex myself.