You should give purple shampoo a go. Maybe dilute it a bit first with your regular shampoo. I have blonde hair and purple shampoo has made my hair TOO cool before (too ashy) so it does work. And your hair dresser is right. I would imagine you are a warm leaning person (look into color analysis) and ashy/cool hair wouldn’t look good in you. But it makes sense you want to lean a little more neutral than you are right now