Huawei Technologies Co.’s ambition in consumer devices over the past year has been to decouple from Alphabet Inc.’s Android software entirely, culminating with the launch of its made-in-China HarmonyOS Next alongside the Mate 70 smartphone in December. It’s the most substantial attempt at building a third mobile ecosystem, outside of Apple Inc.’s iPhone empire and the Google-led Android confederation, and it builds on the company’s considerable reach, resources and nearly a billion existing user...