China and Vietnam are naturally allies as long as they are both communist states, cause the west and US ultimate goal is to kill both of them and whiteys will pull out all stops trying to dominate the east Asians forever.
I know what the CCP planted in your mind a fantasy of the "united Asia", but don't even think for a second that it's possible to replace the US here. Be it military, culture, technology, philosophy, there's nothing of China that you can not find outside of China, and anyone can do the same thing, if not, better than China. Furthermore, China's economic and political models are fundamentally different from Vietnam, just solely based on the level of taxation accountability. For example, Chinese government fails to secure funding through the extraction of direct tax (like Personal income tax (PIT) or property tax) because they lack consent-based legitimacy. States that raise significant revenue from income taxation (like Vietnam in recent years, and traditionally, Western countries) face strong demands for accountability. This is not the case with China. Chinese people don't trust the government with their saving. The PRC has a total disregard of taxation on non-state sectors because it prefers total control over accountability. This model is high-cost and requires long-term commitment. That's why it's absorbing its own private sector. Applying coercive methods and to force compliance is never gonna be successful in the long run, no matter how effective the extraction capability is, because it requires high administrative cost and demotivates productivity. Chinese government is sacrificing their low and middle class, and attacking its private sector on a massive scale for a greater control over economic resources. Vietnam, on the other hand, is democratizing. We can prove to you that we can be better at being communist than China.
Again, PRC is a regime that still mainly prioritizes high efficiency and totalitarian approaches to impose involuntary compliance, that's not much different from how it operated thousands of years ago, in other words,
inferior to the Western models. Western countries can exert control and innovate without silencing its citizens. That state of flexibility is unprecedented in the human history. If you notice, most of our new public policy and management schools are helped built by the US, not China. We do learn from China's failures, but not your successes.
You should worry about yourselves first before worrying about us. Make sure you unify your country before facing the US.