Huawei seems to knows how to make the entire chain of technology it uses, with other available Chinese sources. Their backup solutions may not be the best, fastest, smallest compared with what from the U.S. So, the issue is whether Huawei can improve its knowledge to reach a level of the best, fastest, smallest.
The history of China has shown that Chinese excels in making improvements. For example, the oldest pottery may not be found in China, but China becomes the best pottery maker the world has ever seen. The oldest bronze may not be found in China, but China becomes the best bronze maker the world has ever seen. Making improvement has certainly been a strength of China.
Therefore, this trade war represents a watershed moment in the history of technology that China is forced to make needed improvements for all components used by Huawei not available from the U.S.