Haven't used XMPP much so can't comment on that but in case of Matrix, I use conduit (server) + cinny (client) and it's much lighter and better setup than the synapse and element. Conduit isn't super feature rich nor cinny but if you aim for rich text messages it works well.
In many type of Infobox on Wikipedia, it's Wikidata which is working from the behind and editing the data in such articles is basically being done at Wikidata.
Why Wikipedia though? Wikidata should be one to get this kind of data and all Wikipedia articles has Wikidata items. On top of that Wikidata even keep records of site name, like when someone change their site name.