First of all, thank you. You made me be 101% sure of my opinion to never mix marketing with journalism, and also thank you because tomorrow I have a job interview as a digital editor in an advertising agency, and me as a 25 year old not so experienced journalist, always struggle in what to say at those interviews, do I say I am all for marketing when writing? that my ultimate goal is to sell their product? to write wonders about the brand? And I question myself this all the time because I rather serve the public than to sell a product, serve the public with top quality content and always trust that it would eventually sell the product. I have an internal conflict with this kind of semantic, which concepts should be used for which topic/profession/job title?

Second of all, I think public editor is your best choice, it does not sound pretentious like the other ones and it is just plain simple and significant.