Solved.
MouseMove, 0, 1080
#NoEnv
Sleep, 1000 ;wait 1 seconds feel free to change this number depending on your load times
Send #+{Left} ;Send Win+Shift+Left
Sleep, 1000 ;wait 1 second feel free to change this number depending on your load times
WinActive("A") ;grab the currently active window which should be your game
WinMaximize ;maximize the currently active window
Return
; This section closes PCSX2 when pressing Escape
$Esc::
{
Process, Close, {{{StartupEXE}}}
}