I know where you are because I was there.
When people know what a community is (plus internet, forums, e-mails, civilizated debates, discuss, dialectic) it’s so different when people just don’t knows and joins into some Discourse instance.
Discourse is a forum and you probably need to point a single or no-more-three point/s on your homepage and then show the default Discourse approach.
You probably need to explain how to search, how to contribute and why the forum is good for your community.
If you record some little video, that could be the all-in-one solution for keeping the crowd sharing and not expecting others do things.
You can try all the plugins around but no-one will change the concept that Discourse is a forum and not a Social Media instance.
That’s good, they will love to discuss.