Better stealth is not working it just disables the indicators.
Edit: It seems to be working if I open the game -> get in world -> press ESC -> press ALT+TAB -> open the trainer and tick off better stealth while the game is minimised ->return to the game.
Animals can still detect you at long range when standing up and will run away but not far. If you're crouching and moving towards them they won't see you or hear you. I snuck up on a Blacktail deer and shot it with my shotgun at 11 meters and it didn't detect me even though I was moving through some bushes.