I would box in the soffit similar to this (Google pic). I’d also run the gable soffit first then butt the siding J up to it. Notice in the pic the gable is also proud of the main wall.
There is no venting going on there, so I do not plan on adding soffit. I was planning on just painting it white. Who's going to even look up there?
I just want to figure out how to deal with the notch. Add a piece of J-channel under the cut edge the last 18" or so on the left side and J-channel the 4" vertical drop on the right?
Kinda what I figured.... My concern was the "upside down" piece of J-channel...Yes