This is an application that supports Questions & Answers through a web part that can be used directly on a Modern SharePoint Site without the need for Yammer or a backing Microsoft Team site. It relies on a backing SharePoint list that is hidden and a provisioned Site Page that hosts a pre-configured version of the questions web part.
Open this sample in the gallery (popup panel): Open in gallery
Source: https://github.com/pnp/sp-dev-fx-webparts/tree/main/samples/react-questions-and-answers