There are PC style PSUs rated to up to 1.2kW for 110V and 2kW-ish for 220V outlets for use with crypto mining machines. They are available used way below kW rating for having little values outside of narrow relevant contexts

>> Power Supply: 12 V DC (≈1.5 kW peak)

> That's a lot of juice for 12VDC

Indeed it is. It's 125 amps, which apart from car starting motors is essentially unheard of because of wiring losses. I think the article somehow got this wrong.

At these power levels, rational designs raise the source voltage, then down-convert closer to the loads.