I think you’ve stumbled across Universal Control magic link (I think it’s called that, I’m away from my lg tv atm). I made the mistake of looking in this section, when I was trying to turn cec back on the other day. This isn’t the right place.
Somewhere in the menu lists, there is an option called simplink, make sure this is turned on. Shutdown the pi. Turn off the TV, (At this point it may be worth unplugging the TV and the pi, the recommend time is 10 minutes. I found 30 seconds was ok). Power the the TV back on, put it on the hdmi input/source for the pi. Then power on the pi. CEC should be working now.
I’m front of that TV now, its actually called Universal Control (not sure where I got magic link from), I think it allows you setup controlling the listed devises with your TV remote using IR.
yes there is a step by step process, I found that resetting it and not doing anything at all makes it work, which is a bit counterintuitive, but it works for my RP3.
For me this works all the time, (every 6 months I need to come back to this post to remember what I have done):
You go to the Home of the LG Smart TV screen (called home panel on my 2022 TV)
on the HDMI 1 (in my case) there is a button with the CEC logo on it, called Remote Control Configuration.
There you press Delete and Ok
and that’s it, the pi and LG understand automatically…