Marketplaces are, by definition, multi-sided. This is why they are notoriously hard to start but, also, notoriously defensible. The risk is less technical than it is to get the n-sides into the marketplace, for an arbitrary form of the marketplace.

Therefore, what is the form of the marketplace you can deliver now to validate your idea? In other words: can it be a spread-sheet, Facebook group, online directory, Telegram space, etc... that take the tech out of the equation and that help you create the "marketplace", and then you can port that into your preferred form, informed by the knowledge you acquire running the proto-marketplace?