how to render a node field of a referenced node on the node form
You can create using Views a view with "Entity Reference" where you can make the rendered content you wish to add to the node. Than add a new field of type "Entity Reference" to the node edit form of this node type and set up in section "Entity selection":


Mode -> 'Views: Filter by an entity reference view"
View used to select the entities -> choose the view machine name you have created for this purpose


Additionally, you can provide a comma separated list of arguments to pass to the view.

To avoid some status messages like 'Do something on load', you should uncheck "Test behavior" in "Additional behaviors" section.

Hope it helps