Are you saying no one knows what grade of studs were used or that they refuse to tell you? It is the responsibility of the builder to prove that he met the contract spec, not yours. This is where I would be explaining how to be sure the next requisition for payment will be approved. I don't understand what the concern is about the beam in the window opening. Obviously the exterior face of the opening is covered with plywood sheathing and I assume that will be covered with some kind of weather/air-barrier and/or cladding. I don't see anything in the photo that suggests that work won't be completed properly but you should follow through to be sure. As for bracing, the end of any beam must be prevented from rotating when loaded. I suppose it's required by code but any experienced carpenter should know to do it. Offering blanket criticism about the quality of work from a few photos isn't helpful. Until someone tells me the grade of the lumber, I can see nothing wrong with the work other than an absence of more conservative connection detailing and, of course, nailing at the post. Counter-sunk Timberloc screws from each side would be fine if they are 4" or longer. I've seen the best carpenter's I know make worse mistakes.

Those original lamps are now split between the kitchen lounge and the living room. I think these old lamps are passé now! I had a similar-sized chest on that side and since I had to pull it out to get the ladder in place, I tried this small table. I'd like to find a matching pair of lamps for my master since I like those others in so many places! What about these since they're the same color as my overhead fixture and rods. Modern drum shade? I'm concerned that they're too tall at 31" with shade. These are metallic in color on the base and 27" high: More bookmarked lamps to come...my web has slowed down

I would use that area for storage only. Breathing insulation fibers is not healthy. There is to much duct work, electrical wires, slopes, etc. to make it habitable. You will also end up compressing the insulation, losing its R Value and putting pressure on the ceiling below. You do have a great insulation job up there and a nice storage area now.

I don't know anything about "Gert" construction, but in normal homes the wiring is inside the stud cavities, stapled to the studs or (if added after construction) fished through. If there is space behind your wall surface, that's where your wiring will run. If not, it will have to be installed on the exposed surfaces of the walls. In that case it should have mechanical protection. Wiremold is one well established system for surface wiring. Maybe I'm misunderstanding you, but from what you've posted, it seems that you're building an office larger than some apartments, you're installing an 11+ KW PV system, you already have an EV (presumably a Tesla), and you're talking about buying a Tesla Cybertruck. None of this comes cheaply. It's just a bit surprising to hear of a person who obviously has ample financial resources worrying about saving a few thousand dollars on the wiring for a new building. An experienced professional licensed electrician will know good ways to wire your office. I suggest that you let him do the job. In your place, I probably wouldn't mess with the trenching, either.