bad sector wrote:

I can do that [set NumLock state on boot in the BIOS], but my issue
was with the fact that it's ON by default so every time I load BIOS
defaults it's there again. I suspect that 90% of users not only never
use it, they don't even know what it is so why is it a default?

Because the vast majority of users don't use compact keyboards (no
numpad). They aren't going to use a default for the rare few. For the
majority, they don't want the numpad duplicating the keypresses from the
arrowpad. Why have 2 keys for Up, 2 keys for Down, 2 keys for Home, and
so on? Most users have an arrowpad and a numpad, and they want them to
default to those behaviors. Numlock off by default on boot means the
numpad becomes another arrowpad.

I'm not knowlegable enough to distinguish between
before and after post, and I don't know if the boot
code (strictly grub2) deals at all with usb.

Unless configured to show an ad banner (usually showing the brand name)
which obliterates the POST screen, the POST screen shows information and
detected devices, waits 1-3 seconds (sometimes this is configurable),
and then loads the OS bootstrap code into memory and passes control to
it. When the POST screen disappears, you're into the OS load phase.