It's definitely "just buy one", if you just want an inverter.
It is nonetheless interesting if you want to build it as component of something more complex, say DIYing a battery bank out of some recycled cells
I wonder how many changes would be required to run the whole thing on say 24 or 48V. At glance just powering the board with 12V source and just feeding more to MOSFETS seems to be enough
Seriously though, there's enough energy in those numbers to seriously mess you or your electronics up. It's not quite like a bottle of old nitroglycerin, but it's definitely enough energy/power that you must respect it.
They aren't dumb. They are professionals who do this sort of thing for a living.
That said, most companies don't etch their own boards. That part of the build process could be skipped by sending your schematic out to one of the boutique board fabrication places. They aren't terribly expensive and it avoids having to deal with nasty chemicals. The article even mentions this and I would highly encourage it myself, at least until you have a few boards under your belt and are feeling more comfortable with diving deeper into the process.
Assembly carries a different set of risks from powering something up. But as the sibling comment says, the assemblers are skilled technicians. They might lack theoretical background but they will have had a lot of apprenticeship.
The EGS002 looks like a really neat subassembly. It's just that at 1kW the safety issues are significant.
It is nonetheless interesting if you want to build it as component of something more complex, say DIYing a battery bank out of some recycled cells
I wonder how many changes would be required to run the whole thing on say 24 or 48V. At glance just powering the board with 12V source and just feeding more to MOSFETS seems to be enough