When someone joins my discourse group, is there a way to grant certain permissions to access/post and comment in a particular sub-category?
Currently manually granting permissions to be able to comment/post.
Is there a way to automatically give a new user a specific role when they join, either from an invite link or predetermined email…so that it will automatically enroll them into the group and permissions
Yeah there is. It links with @osioke’s group security settings he linked above. When you invite someone you can add them to a group. As you can see you can also restrict the invite by email so that only that person gets the role.