yeah electrical problems are like the hardest to fix imo. have you tried replacing the lcms at all? maybe swap with a local fanatic (no tamper dot if you don't drive anywhere). then you can do the turning on the car, test headlights, turn it off and see if the code pops up. that's the only way i know to test an LCM short of buying a new one lol
probably try looking at the wires and see if there is a break anywhere. and also clean the OEM ground points. they are located behind the headlight so you'll have to remove them.