B767 First Officer reported a strong electrical burning smell during climb in the cabin. After troubleshooting and conferring with Maintenance and Dispatch the flight crew requested priority handling to a suitable airport where a safe landing was executed.

Narrative

Plane had electrical issues from the beginning. Cargo doors couldn't open. Maintenance advised us to reset the utility busses. Didn't finished downloading ZZZ-ZZZ1 until we were almost fully loaded with Passengers. No one told us this at this moment. Eventually all sorted out. We get going. IFE (In-Flight Entertainment) kept tripping out and restarting on the Flight Attendant (FA). Didn't think much of it. Because there was a previous write up about it that screens went out toward the back of the plane. We start climbing out. I head back for my break. As soon as I stepped out of the cockpit I got hit with a strong electrical burning smell. First thought it was the galley and something was burnt. Go to the lav. Set up the curtain. Sit down for a second. Smell only getting worse. The purser comes up to me asking me if I smell it too. I was like yeah. I was trying to process the info if it was really something to be concerned about. I call up to the front; let them know we got a strong electrical smell. In the mean time looking everywhere for where it's coming from; no actual smoke. But the smell is very very present. Get back up in the cockpit. Help with the checklist. Still cannot isolate the location. Get Maintenance Control and Dispatch in the loop and decide to divert to ZZZ2 since we were just north of ZZZ2 at the time. 15 minutes to ZZZ2. Runway XX to ZZZ1. If we knew where the odor was coming from exactly. Maybe would have went back to ZZZ1. But since we had no idea and it was still present and unknown we went for nearest suitable airport. Requested Priority. Fire trucks followed us to the gate. Landed overweight by about 6K. We get to the gate; lights start flickering. Fire department said there is no presence of a fire from thermal imaging.