First, head to HKEY_CURRENT_USER\Control Panel\Keyboard. Double-click
the “InitialKeyboardIndicators” value in the right pane and set it to
“2”.
Next, expand the “HKEY_USERS” folder. You’ll now need to repeat the
above process several times, changing the InitialKeyboardIndicators
value under each folder inside the HKEY_USERS folder.
Start by going to HKEY_USERS.DEFAULT\Control Panel\Keyboard, and
changing the InitialKeyboardIndicators value to 2. Next, repeat the
process for the folder below the .DEFAULT folder–it’ll start with an
“S-“.
Repeat this process for the remaining folders inside HKEY_USERS,
changing the Control Panel\Keyboard\InitialKeyboardIndicators setting
under each one.
Next, shut down, then boot the computer back up again. When you
reach the login screen, press the Num Lock key once to enable it.
Don’t log into the computer. From the login screen, click the power
button and select “Shut down” to shut down the computer again.
Boot the computer back up and Num Lock will be enabled on the login
screen. It seems that this puts Fast Startup into a state where it
will automatically enable Num Lock at every boot.
https://www.howtogeek.com/244606/how-to-enable-num-lock-automatically-when-your-computer-boots/