M1 Macs don’t have UEFI, just a very limited system that can boot macOS from the SSD. The boot menu is macOS. The initial firmware has no drivers beyond the SSD. That’s why there is such a long delay between power on and the screen displaying the logo. And why there are no keyboard shortcuts. And why it doesn’t support external boot discs.

https://news.ycombinator.com/item?id=26114417

https://support.apple.com/guide/security/boot-process-secac7...