If you hadn’t already, install the latest version of Views and create a new View with a block display that shows only Related Content CT. On the right side, open the Advanced options and add a new Relationship of the type:
Entity Reference: Referencing entity (you’ll find the description underneath as being A bridge to the Content entity that is referencing Content via field_related_content – or whatever you named the Related Content field in the Article CT). Click Apply and on the next screen check the box:
Require this relationship” and add an Identifier to what you prefer.
Next you need to add the Contextual Filter in order to display results in this block that relate only to your Article CT.
Add a Contextual Filter of the type:
Content:Nid and click Apply. On the next screen, under Relationship, select the Identifier of the Relationship you had just added in the Relationship section. Below, under When the filter value is NOT available, select
Provide default value of the type
Content ID from URL.
Lower, under When the filter value I