Qualcomm has asserted that some of its Snapdragon Wear SoCs are compatible with Wear OS 3.0, despite Google's continued silence on the matter. Apparently, the Snapdragon Wear 3100, Wear 4100 and Wear 4100+ 'are capable' of running Wear OS 3.0, whatever capable means in this context.
https://www.notebookcheck.net/Qualcomm-claims-that-its-Snapdragon-Wear-3100-Wear-4100-and-Wear-4100-platforms-are-Wear-OS-3-0-capable.546060.0.html