I have a rooted LG C4. Beyond blocking things at the DNS level, not accepting terms, not using AI, I wonder if there’s some existing software solution or a documented step-by-step to remove this bloatware/spyware.

It'll be difficult. It's webos of which there's very little custom development.

You'd be better off with an android tv which you can poke at using adb and disable services. Maybe even root it. And install alternative software like smarttubenext.

Unfortunately there very few Android based TVs left. Phillips recently switched to Titanos, Samsung has tizen, Amazon has a new OS. I think it's just Sony that's left on android now.