Yeah, that thing about your stress dropping by half really hits home. I read an article that called checking work email at night a "digital leash." It basically said your brain never gets the signal that work is over, so you're always a little bit on. Setting that hard stop at 6 PM is like giving yourself permission to actually clock out. It makes total sense that it would cut your stress down so much.
My buddy used to check his phone for messages right up until bed. He started leaving it in the kitchen after dinner and said it was like a weight lifted off his shoulders. The quiet time let his brain finally switch off from work mode.