"Hey Siri, turn the brightness all the way down." Works for me for the first one. Don't pause after hey Siri; just make it one smooth utterance. For the secon

"Hey Siri, turn the brightness all the way down." Works for me for the first one. Don't pause after hey Siri; just make it one smooth utterance. For the second one, not sure how you do that even with today's phones.