Yes, it fits well, I have it together with an RTX4080 in the case. I would pay more attention to the CPU cooler, as I don't have much space between the graphics card and the cooler.

The verticalmount kit from NZXT fits into the NZXT cases H5, H6, H7 and H9. How close the GPU is to the glass depends on the GPU model, but you will generally always have more distance to the glass if you install the GPU vertically.

Yes, I have this box and I was able to put it on.