I have spent 2 days trying to figure out how I can change my mouse pointer speed in Windows 11 using AutoHotKey. I have done some research and wrote this:

toggle_speed := false

^j::
{
    global toggle_speed
    if (toggle_speed = false)
    {
        SetDefaultMouseSpeed 1
        toggle_speed := true
        MsgBox "The toggle is now ON"
    }
    else if (toggle_speed = true)
    {
        SetDefaultMouseSpeed 20
        toggle_speed := false
        MsgBox "The toggle is now OFF"
    }
}

There is now such effect after running and pressing the key combinations.