Good question, it's mererly because I was using an ITX case with those hardwares, but it's not easy to fit the case behind the TV, so I came up with this solution. If I start new, I might choose ATX instead

Only a video cable + a wifi antenna for now. The power cable is on the other side and is hardly noticeable.

Thanks! I can still see it from the side lol

CPU fan can get noisy at full load. Could use a better cooler, this one is just what I already have and is okay so far

Yeah IKEA also has a gaming line, however nothing about a gaming PC

There is a 20mm space from the GPU’s backboard to the pegboard, should be enough