I had similar issues. My LG remote would power on/off but this was the only key that worked. (Red Power button)
I tried changing the batteries but they were OK.
I tried resetting my remote by removing batteries and pressing every key for 3 seconds (this didn’t work).
I tried re-pairing my remote control by pressing Home and Back for 5 seconds then pressing the wheel. This indeed re-registered the remote control but still no buttons working (except red power button).
**** Here is what fixed my remote control. ****
I used the LG App on my smartphone to navigate to the Settings then General and then turned off Quick Start+
Then I turned off my TV (it was slower to turn off) Then I pressed the remote red power button and when the TV came back on, everything was back to normal again and the remote control worked as normal.