Often doing prototype casings are nightmares for many electronic hobbyists with limited resource. We can design, draw and make a soplicated electronic PCB but not a good-looking housing. Often we do not have tools such as milling machines in home to open rectangular ports.
And I have an idea about prototype house making: Is there a thing in the world which is like LEGO toy but pinpoints on prototype making so that we can make the casing just by stacking fundamentary elements?
There is a near infinite number of possibilities for the hobbyist.
You can solder scrap circuit board together, and make little boxes.
You can put things in tin cans that food originally comes with, indeed I once tried some seitan that came a in a tiny can and while I wasn't that happy with the food item, I bought some more for the cans.
Decades ago, someone at school was more interested in the finished product than the electronics. So he'd buy kits, and then put his effort into making nice wooden boxes for them. For some people, wood is something they can work with easily.
Get a metal brake, and bend sheet metal for your boxes.
Electronic equipment that's tossed out can often provide interesting boxes. Either the whole thing (such as an old stereo receiver with the guts taken out and a new front panel, again circuit board can be that panel), or inside where there may be small tin boxes for shielding sections.
At least in North America, you can get metal utility boxes that have two halves in the shape of a "u". I've cut those down when a standard size has been too big.