I'm thinking social is socia, media could be komunikila and manager could be administranto, but that all feels very clunky. Any idea for something that sounds much better?
I think that the best translation for social media is sociaj retoj. The job of a social media manager is not to administer social media, but to represent another organization in social media by communicating the organization's goals and ongoing work to the general public via social media. For this reason, I wouldn't say soci-reta administranto/administristo, but rather soci-reta komunikisto.