When the wall above the fireplace has no studs

Описание: How I solved my problem of mounting a large TV above the gas fireplace.
I cannot mount the TV on the wall without proper support. So I added it. This took an afternoon to complete.
The house was built approx 2002. The house, like most in the neighbourhood, was built with a bumpout on the exterior for the gas fireplace, and the exterior has siding where the bumpout is. The highest point on the bumpout roof where it joins the exterior wall is somewhere in the middle of the stud-less area. Where I show the wall with the insulation removed, you may be able to see nails poking through the outer foam insulation. That’s the top of bumpout roof.
Drywall screws I used are 1” long.
Not shown or discussed in the video is cutting out the drywall. Angle the utility knife blade slightly when cutting through the ~1/2” drywall so the back is smaller than the front (like a rubber drain stopper). The blade should not cut much deeper than the drywall is thick.