I don’t disagree conceptually, but English has been a lingua franca for a long time now.

Close. It’s flea market.

It’s not that bad. It’s just German for flea market. And English speakers shouldn’t have an issue with at least “Markt”. Not far from a cognate.

Definitely better names but I think the bigger hurdle is getting the critical mass to get something like marketplace to work in the fediverse even with the perfect name.