I'd try finding a community to where I'd like to post a given article, and look for its posts in the OG instance as well as in instances I have accounts on for other engines (the 3 major thread-oriented ones I know about are Lemmy, Mbin and PieFed). Other than that, of retarded/delayed results but still something I'd recommend, is to follow people in other instances (Mbin / microblogging / Peertube thing), and interact with everything the user finds so posts can propagate across instances, so at least in future searches, others, or even yourself, may find/refind posts more easily.