Apple Silicon Startup Manager and iBoot

Hi,

Where is the Apple Silicon startup manager located? What I mean by this is: is it burned-into the BootROM chip, or is it stored on the internal SSD?

The reason I am asking this is because I want to know if I can still access the Apple Silicon Startup Manager by holding the Power button at boot, even if my internal SSD is completely wiped. By completely wiped, I mean going into Disk Utility, selecting Show All Devices and erasing the top-most disk in the sidebar.

I know that completely erasing the internal SSD on Apple Silicon would cause you to be greeted with an 'exclamation point' screen, with a link to Apple's website that directs you to do a DFU restore with Apple Configurator 2. However, if I had a pre-made USB bootable installer, could I still boot into this by holding power button at startup and re-install macOS that way, instead of Apple Configurator 2?

Any normal PC, including Intel Macs, would always allow you to boot into a USB through their respective Startup Managers if the internal disk is wiped. Hence I would like to know if this is the same with Apple Silicon Macs or not.