Help with 4 year old who will not be quiet ever

My 4 year old has ADHD and accompanying SPD and is never quiet or calm. The problem is he has stopped taking naps but my 1 year old still very much needs a 2-3 hour nap every day. I cannot for the life of me get my 4 year old to be quiet. Not with the iPad, tv, snacks, etc. He is running around screaming and banging around toys like usual. I’ve tried talking to him, pleading with him, offering bribes, and eventually punishing but nothing works. My 1 year old is MISERABLY overtired every single day with bags under his eyes because he can’t sleep. I’ve tried fans and white noise but my 4 year old is just too loud. What do I do?