What does a thermal shot of the bottom show? If the current photo is from the top, then the heat that is showing in the middle is likely coming through the circuit board from the bottom metal of the case. Which would mean it is much hotter than what shows.
Could be they had a lot of them already
Whenever people do DIY amps they twist any wires that have AC to reduce the magnetic field. Yet it doesn't seem to be a common practice in a lot of manufactured amps. It seems like it would be even more critical with things crammed in a small space like this. I'm a much bigger fan of the spread out and separated by a wall design like the Akitika. Where only DC crosses the 'wall'. But then it isn't a cute little desktop amp.
It would be disheartening having marketing tell you what to build, how big to build it, how much to spend and what features it has to have.