Hi ,
Some users have been experiencing this issue of the keyboard not working after the first startup and resolved it by disabling fast startup.
Disable fast startup.
Go to Control Panel > Hardware and Sound > Power Options > Choose what the power button does > Change settings that are currently unavailable > uncheck the Turn on fast startup option > Save Changes.
Open the command prompt (admin) and run the commands: sfc /scannow and dism /online /cleanup-image /restorehealth, wait for the process to finish and restart the computer.
Access the BIOS and disable the fast boot option.
Give feedback if the information was useful or not.
Thanks