According to Dexcom, the current version of Wear OS supports the app. However, the watch cannot be paired to the transmitter directly.
Check and confirm that your mobile device is also compatible with Dexcom.
You can find the compatibility requirements of the Dexcom app on this site: https://www.dexcom.com/faq/what-devices-and-software-are-compatible-dexcom-cgm-apps