Huawei made a big mistake by not fully open sourcing HarmonyOS, you can't flash OpenHarmony so it doesn't count.
I feel like Huawei missed a gigantic opportunity there: forking AOSP may have gotten them traction. I would totally buy a Huawei device if it could run GrapheneOS, and I wouldn't mind if GrapheneOS was based on Huawei's fork rather than Google's.