Luke in ROTJ puts down his lightsaber to face the emperor - the darkest man in the universe.
Luke in TLJ takes out his lightsaber and considers murdering his nephew in his sleep because he MAY turn to the dark side.
sounds like the same dude to me.
I love these cherry-picked arguments, where you completely ignore the fact that ROTJ Luke tried to kill the emperor despite knowing he shouldn’t.
And the “MAY turn to the dark side thing” is your misinterpretation, because that’s not what Luke says in the movie to Rey. It’s quite clear the way Luke tells the story that Ben WILL turn to the darkside (if he hadn’t already).