Watched your youtube video (https://www.youtube.com/watch?v=HJ2CVG5Xbko). Exact same symptoms with my LG fridge. Replaced PCB, no change in issue (did that fix yours in that video?). All fans run in test mode, compressor running, but temp in fridge is consistent at 44 degrees, temp stays at 36 degrees in freezer. Can not get temps to go lower (with settings at 37/0 and lower). So not exactly 'warm', but not getting colder either (with the new board). Did you need to change anything else? Any ideas for next step? This is first issue with fridge, and just started 2 days ago. Fridge approx 5-6 years old.
I took freezer apart to access evap coils, found ice build up surrounding thermistor and sensor coils (thinking that may be my next step - replace thermistor and sensor):