The only electrical mod I have that isnt direct plug and play is my dash cam, and even then its 'add a fuse' type. Everything else is interior bulbs, diode dynamics fogs and license plate lights.

They have asked me to start with removing the LED headlights, and then continue one by one with other items. The bulbs are Auxito direct plug and play, but of the higher wattage variety witha built in fan.
(AUXITO H11 LED Bulb 6000K Cool White)

I will feel really stupid if this is related, but for now I am following through with what they asked.

FWIW, last time the warning light went on, I scanned it with a bluetooth reader and no codes were present.

Also discussed with 2 former Toyota techs, and neither think they are even on the same circuit, so who knows. During the last inspection my seat heaters and rear window button stopped working too, but thats likely just the fuse. Havent had time to look.