Heading tags are used to help Google and users better understand your content. I just read through the official Google guide on SEO https://developers.google.com/search/docs/beginner/seo-starter-guide
Just have a look at the section https://developers.google.com/search/docs/beginner/seo-starter-guide#headingtags
The section starts like this:
Similar to writing an outline for a large paper, put some thought into
what the main points and sub-points of the content on the page will be
and decide where to use heading tags appropriately.
I believe your scenario fits the above use case. Obviously Topic1 and Facts/Discussion don't belong to the same level in the hierarchy. If you draft an outline for your document, you will include Topic1 but may choose to skip Discussion.
(In a logical sense, a reader should clearly understand that the fact/discussion is about the topic1. Hence topic1 is above discussion in the hierarchy and will preferably find a place in an outline.)