As far as I remember,
Wiki used to be a source of knowledge base across many working groups before 2018. Check this Magazine article “Fedora’s Documentation Website has been overhauled”. Many wiki articles were converted to Docs using wiki conversion script. Wiki vs Docs is best explained in this thread.
Docs: Documentation sites were incorporated into Antora static site generator that combines different Git forge. The Fedora Project respects a decision of working groups/SIGs. Since 2022, many working groups/SIGs moved to GitLab. Still, it is confusing for new contributors why one has to work on different Git forges.
Docs articles are maintained, peer-reviewed, and version-controlled. It requires certain routines and processes that are natural for developers. For those who are not familiar with it, there is a learning curve that worth learning the ropes.
The Fedora Magazine is, by definition, “a website that hosts promotional articles and short guides”. Although some of short guides are very comprehensive and self-containing, the content that needs updating is not suitable. I don’t see overlap between Docs and Magazine in its inception. But some how-to articles in the Magazine can be found also in Docs, which looks duplicated.
Fedora CommBlog: It doesn’t publish knowledge articles. What is being duplicated?
And other platforms - even Fedora moderated accounts do not publlsh knowledge articles.
Discourse: we have been discussing this topic on other threads. I recall you will be running a poll.
Matrix/mailing lists: it is irrelevant here as a knowledge platform.
Back to the point, I’m sharing what works well in Pagure and what doesn’t after trial and error. Nobody told me. I moved on and documented the guides and removed duplication.
As @pboy shared his view on tool vs content on other thread, platform integration and preference on tools are not related to quantity and quality of documentation.
I grew out of confusion and duplication. I learned a ton from challenges faced by Docs team. Help make us less confused and dedup content. I did my part.