The TTGo T-watch K210 could be the basis for a smartwatch project, with Lilygo incorporating a display, a camera and Wi-Fi. The K210 supports Bluetooth 4.2 and has a USB Type-C port, too.
https://www.notebookcheck.net/Lilygo-T-Watch-K210-A-cheap-base-for-a-smartwatch-with-a-display-camera-and-Wi-Fi.469100.0.html