If you're save scumming to get ghosting and getting frustrated at alerts then I don't know what to tell you. It's not supposed to be effortlessly easy to ghost through the game. The level, AI, encounter, and game system design are built specifically to encourage involved play, which can include alerts, baiting, retreating, and adapting to situations. I feel strongly that the point of these games is to accept when a mission doesn't work out quite as you intended, even if it's just triggering an alert, and making the best of the situation. Getting frustrated at the stealth, getting caught, and refusing to adapt in preference of ghosting thus leveraging repeated save scumming is more just forcing yourself to have a frustrating time.