Just wanted to chime in since you specifically mentioned the "65" LG OLED", which is the same TV I have (specifically the OLED65B6P). When plugged into the internet it has all of the usual unfeatures (including ads displayed over hdmi input), however if you leave it unplugged from the internet it works great and boots up almost instantly to the last input selected without any fuss. Furthermore, the HDMI CEC commands work as expected (in both directions--control of the tv from the computer and control of the computer from the TV with all of the expected buttons on the remote being passed through). The set is also quite good about supporting legacy S/PDIF (optical) passthrough so I haven't needed to replace my receiver.

So far the only feature I have been unsatisfied is that for some reason the set does not auto-shutoff when the hdmi input is not active. For example, I had it hooked up to a computer which was set to turn the monitor off after 15 minutes and instead of the TV shutting off it displayed an 'input disconnected' screen. As a stopgap solution I set the computer to have a 'screensaver' that is all black instead of turning the monitor off--which works pretty OK since the OLED is completely 'off' when displaying a blank screen. The only downside is that the the electronics in the TV stay running, so the power consumption in this state is about 20w.