Good evening,
I have the same problem with my game. I recently bought the game in order to play LSPDFR... But it does not work.
I have the message "Could not hook game process ..." Just like you.
Before I start, I need to mention that I have got a Rockstar Game version. Not a steam one, so nothing to see with "commun" files etc..
I turn my AV off, Windows defender too.
I installed ScriptHookV.asi, ScriptHookVDoNet.asi, I followed your steps through OpenIV.
I have my game updated, as well as RageHookPlugin (.50)
I searched everywhere on the web... I do not understand why it still does not work...
Could you please try to help me ?