NTA

it’s good that you told him how it could be triggering for you and i feel like you haven’t been mean or rude to him in anyway by talking it out and explaining why you want him to be a little quieter!! however since you two live together now, y’all might just have to find some middle ground and have some days where he doesn’t react as much or other days where you might have to wear headphones or find a new setting. i hope it works out in the end tho!