Sorry.
The above described feature seems very powerful as a data source ( reminding me on data views in obsidian).
As tested above, there is no oneboxing / preview support built in (yet), which would render results inside a post, as other links inside already do:
With additional options (for example how many topics to display) this would allow a dynamic meta overview of other topics inside of topics.
Side note: I had to change the example onebox link above, since splitting topics breaks links to posts. I would like to learn, how to prevent that.