Your job description probably covers about 30% of what you should be doing.
It probably prioritises being reactive over being proactive.
It probably doesn't embrace the full community management framework.
It probably wasn't written by someone that has ever done your job (or in many cases has much knowledge of it).
The problem with community management job descriptions is they usually won't lead to a successful community.
It's a list of tasks that are involved in building a community. It's not a complete list (or close to one). It's not even a list of the most important tasks you should be doing.
If you want to really build a true, thriving, community, you're almost certainly going to have to go far beyond your job descriptions. You're going to have to embrace the full community management framework. You're going to have to master the community management lifecycle. You're going to have to be really good at diagnosing where your community is now, where it has to go next, and executing actions to get there.
That means you're going to acquire certain skills (online influence, persuasion, momentum-building, community organizing) that you don't have when you take the job.
Therefore, you either need to work for a company that will let you get on with what you need to do, trust that the company cares about the outcome and not the process, or find a company that will let you do real community building work. You're the expert, not them. It's a tough decision, but your community needs it.