As this project appears to be fairly unknown in the fediverse still, I’d like to use this opportunity to advertise Flohmarkt. This Fediverse equivalent of Facebook Marketplace already has some instances up and running - see here: https://codeberg.org/flohmarkt/flohmarkt/wiki/flohmarkt-instances
The latter. Though given the downvotes, I think people are either not smart enough to get it, or too smart and think I don’t get it.
You just said what everyone thinks when they hear ‘lingua franca’ for the first time.