You can create as many applications as you want. User grants of custom OAuth scopes are not fully implemented, as mentioned in that GitHub issue.
You could work around that by creating an application for each type of access, or by using roles within an application. If you had a blog, for example, you could create an admin role, an editor role, a contributor role, and a subscriber role. You could use a lambda to assign the roles to the JWT ( see example here: https://fusionauth.io/community/forum/topic/281/implementing-a-role-based-access-system-for-authorization/2 ).
Then your application could examine roles in the JWT and provide appropriate access.
Hope that helps. Feel free to respond here or in the forum if you'd like to discuss further.