Huawei is expected to launch the Watch 3 series in a few weeks, which should comprise the Watch 3 and Watch 3 Pro. A recent certification document all but confirms that Huawei's next smartwatches will run on HarmonyOS, rather than the LiteOS that the company currently uses.
https://www.notebookcheck.net/Possible-Huawei-Watch-3-certified-with-HarmonyOS.539445.0.html