schema.org – Marking the right outline for a large article with a question and related topics?

I want to mark some pages of articles in a corporate site with an outline.

The articles have around 3000 – 5000 words and some of them focus on a question and its answer. A typical question might be like "What is religious faith?" His answer includes some related topics such as "Christianity", "spirituality", etc. At the end of the article there is a summary that gives a shorter answer.

How to connect the article of the article with its themes using the properties "about" and "mainEntity"? I would like to express that the article focuses on a certain question / answer, but also marks some understandable and recognizable topics such as "spirituality".

It's okay. To use both, about and mainEntity, on the same level, side by side, although mainentity is a subproperty of approximately?
Then it would look like this: