Consult with a specialist what the option option would be.
A really good looking and expensive chair can be just as bad for your back as a $100 chair.
When sitting in a chair 6+ hours per day it is important to have a good chair. You probably can't get such a chair for less than $500-$700.. but it will be worth it in the long run
Some chairs might be good for others but bad for you since your backs might not be build same way. so best thing is to consult a specialist