Dynamic Parent ID in Query Loop

Is it possible to get the Parent ID of the current Page and have it dynamically populate in the “Child Of" for my query loop?

Use case: We have “About Us” as a parent page. The child pages of “About Us” will have a template with Sidebar Menu. I want the sidebar menu to only display Children of About Us.

I want to use this same template for another “Page Parent” and its children.

If I refer to parent page ID explicitly for “Child Of”, I need to duplicate the sidebar menu and use conditions to display/hide, or use different templates for each Page Parent.

I understand using CPT is ideal (which I am using) - but we also have generic “Pages” that can benefit from this.

{echo: get_queried_object_id()} if I understand correctly. You need to whitelist it with filter first.

How do you have your elements setup? Make sure have the query on the parent element.