AHK script designed to toggle based on CapsLock Status always toggles on 'off' and I cannot change it to 'on' - toggle

Question

(Note: Very new to scripting, borrowed some phrases from other scripts I've online.) I have Carpal Tunnel and play a video game that does not have any key-bind options not set to the F1-F0 keys so I want to rebind the F1-F4 keys to Z-V but only when capslock is enabled, to prevent being unable to type in chat windows and in other programs without closing the script. However, the script re-binds the basic keys to the f-keys ONLY when capslock is OFF, rather than allowing me to change it to ON. Not sure why.
I've tried 'hotfixing' it by rebinding it to Numlock, but when I moved to CapsLock changing 'OFF' to 'ON' did not keep the script from only rebinding the keys while CapsLock was OFF. Not sure why.
$Z::
GetKeyState, state, NumLock, T
if state = D ; NumLock is toggled ON
send, {z}
else
send, {F1}
Return
$X::
GetKeyState, state, NumLock, T
if state = D ; NumLock is toggled ON
send, {x}
else
send, {F2}
Return
etc...
etc...
I expected changing the value 'OFF' to 'ON' would result in the key rebinds only happening during the CapsLock status being toggled on.

Answer 1

Have you checked if you restarted the script after making changes? It's a very common mistake, not only among beginners. According to your example, your keys Z..V should behave as F1..F4 only when the NumLock is toggled off.
Given the nature of your script, you can consider to add the directive #SingleInstance Force which will automatically replace any older instance of your script by a new one each time you run the script again, making testing easier.
You can do conditional binding much easily with an #if directive, which makes the subsequent hotkeys and hotstring only effective when a condition is met.
To check the state of the CapsLock or NumLock keys you can also use the built-in function GetKeyState, which for toggle keys, such as CapsLock or NumLock, with the "T" mode returns either True or False based on the toggle state of the key.
Also, if you want to remap keys, you can simply write the target key's name at the right of the hotkey, which will completely bind the keys, on both Down and Up events. However, for this to work, you must specify your triggering keys as lowercase, since specifying uppercase would only trigger the remap when pressed the keys with the Shift key as well (the CapsLock would have no effect), and that is not your desired behaviour. [More on remapping keys]
Here is an example of what you could do:
#If GetKeyState("CapsLock", "T")
z::F1
x::F2
c::F3
v::F4
Note that, since key remapping always uses the keyboard hook (because it needs to register the Up events as well), there is no need to use the $ prefix in your hotkeys at all.
Nonetheless, you can automate your script even more if you use as condition for your hotkeys the currently active window and bind them to your game using the #IfWinActive directive.
However if there are also chats in the game, you might want to combine both conditions in a single #If, using the built-in function WinActive like this:
#If GetKeyState("CapsLock", "T") and WinActive("My Game Title")
z::F1
; ...
You can check how to narrow your search for the window by its title on the documentation for the WinTitle parameter.
If you want to improve your script even further, you could explore if there is any detectable change on the game window when the chat is active, such as if a certain control exists (you can check that as if it was another window using the WinExist function to check for a certain Window class.
To seek for such changes, you can use a script as the following (from the MouseGetPos documentation):
#Persistent
SetTimer, WatchCursor, 100
return
WatchCursor:
MouseGetPos, , , id, control
WinGetTitle, title, ahk_id %id%
WinGetClass, class, ahk_id %id%
ToolTip, ahk_id %id%`nahk_class %class%`n%title%`nControl: %control%
return
Which would allow you to see the window information of the windows below your mouse. You can use it to check for the name or class of the chat control by placing your mouse over it.
However, keep in mind that many games do not use Windows controls at all in their interfaces and rather just draw them on screen by themselves, so if you're trying this and can't progress much after a while you shouldn't waste too much time on it and rather enjoy playing with your CapsLock toggled binding.
Another tricky way to check if the chat is active is searching for an image on the screen or a pixel color using ImageSearch or much simpler PixelGetColor, but you can only do that if your game's interface is not very complex/animated.