Ja. Do remember that using your 5v 3A target, that is of course 15W. To pull that using a Vcore of 400mv means supplying 37.5A to the chip. A good place to start for resources is TI.
https://www.ti.com/design-resources/design-tools-simulation/processor-fpga-power/overview.html
https://www.ti.com/design-resources/design-tools-simulation/power-stage-designer.html

AFAIK Vcore for Sidehacks Compac-F is 410-425mv which helps a bit with the current but more to the point allows for more stable operation at high speeds. Can't say I've bothered to look at mine but I believe he uses a buck controller driving MOSFET's. And yes, TI has some rather nice controllers as well as matched power stages to work with them.