Just throwing in my 2 cents from previous vehicle.
Before the Mitsubishi I used to drive a made in China 7 seater van.
Called the Hafei Minyi. It had a few problems and one of them is when all electrical power suddenly cut off while driving.
Once cooled down power will return and it can be started.
Managed to trace down to a bad main fuse. In my case a 80A metal strip fuse. The fuse has a crack in the middle and due to engine heat, it will expand and the contact separates at the crack and the whole car will shut off. It took a while to figure this out.