Harmony is the OS by Huawei.

HarmonyOS (more accurately, HarmonyOS 5) is the “homemade” OS by Huawei, since they were blocked from using modern Android (which was what HarmonyOS 4 as well as the glubal was using) that launched in mainland China. They have made their own kernel and a few other bits, removing native compatibility with normal Android APKs, but it’s not as ground up as Huawei would like you to believe, a lot of the bits have been borrowed from Android 12. I believe it is partially open-source (the “OpenHarmony” bits) but, like Android, there are lots of proprietary blobs too.

It’s kind of neat to have a competitor, and it has been successful in mainland China, due to the huge popularity of Huawei devices there (who are like Apple where you need to be in the “ecosystem” with laptops, tablets, smartwatches, earbuds, smart home, even EVs now)

I still think mobile Linux is more useful as a competitor against the “big two”, since Huawei is no better than Apple or Google, they are all giant for-profit companies

In the US, iPhones and Samsung phones are highly subsidized by phone carriers. Motorola to an extent (mostly low end models). Also, Verizon blocks other phones from their network. Check what they sell on their site and you’ll see what’s available to buy as an American. Americans have much less disposable income, so you’ll notice there’re huge subsidies for consumerism; Americans have to be goaded into spending money with discounts or else they won’t buy; it’s a cultural thing.