Having an OS for cars and devices is nice, but it's not a replacement for an OS in mobile phones and desktop computers, especially if Google and Microsoft are going to be allowed to occupy this space. We've seen that control of this space allows the US to basically ban pretty much any software.
Huawei's smartphone brand isn't the issue, there are plenty of other Chinese OEMs with brands. Huawei's software ecosystem (HarmonyOS, AppGallery and HMS) is the issue-- that is the only area where China now has a fledging independent software infrastructure for phones and computers. This is pretty much the only good thing that came out of sanctions. They must hold onto that at all costs because without it, you are back at square 1 and you could get sanctioned by the US at any time.
Hopefully this is just a rumor and it's false.