

This would vary based on what router you use, but this is the way I handled it on my Ubiquity EdgeRouter.
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I added a DHCP reservation for my TV so it’s IP address on my local network doesn’t change.
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I added a new firewall policy (with the highest priority) that accepts all traffic by default between my internal LAN network and the WAN interface of my router.
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Then I added a rule to that policy to drop traffic from the IP address I assigned to my TV.
Now the TV can no longer phone home to send obnoxious notifications or issue surprise firmware updates but I can still turn on the TV and adjust the volume over the local network. I use Home Assistant for this, but I think the LG remote android app would still work as well.
This is basically how I do it too.
I used to be more creative but then I got in the habit of running more servers and swapping hardware more frequently so it got harder to remember what hardware I was actually connecting to. Now they get hardware based names and everything else is named by service-based Ansible roles.