Don’t just watch them. Watch them in order with the knowledge that the first movie was a serious attempt at horror. But the audience thought it was ridiculous and became a bit of a joke.
Then the second movie was an attempt at both leaning into the campiness a bit but also trying to still make a good horror movie.
And finally the third movie was where Sam Raimi realized “fuck it. I guess I do silly horror now. Let’s rock and roll!” And finally was have the masterpiece that is Army of Darkness.