I have an LG C1, which is an amazing TV, but even after disabling every single ad-related option, I'll still occasionally get a pop-up ad when the TV turns on.
Interesting! I have the same TV and never see ads (I'm on the latest WebOS update). My Pi-Hole actually blocks everything and the only times when I see ads are when I disable the blocking to be able to access the app store.
Edit: To clarify, ads served on the WebOS interface. YouTube ads are still there.
Edit: To clarify, ads served on the WebOS interface. YouTube ads are still there.