Mac Starting with USB

I’m trying to restore a copy from a Catalina in a new Big Sur. As it is not starting, I’m trying with the INACCESSIBLE_BOOT_DEVICE procedure. But I have no F10 key, so I cannot access to command at the beginning, just install the new Windows. Is there an alternative way to access to command?
Thanks

The easiest way is to plug in an external keyboard via USB.

tim