Are Zhuang people doomed not to speak fluent and standard Mandarin?

No one is born bad, and Zhuang people speak Mandarin very well. For example, there was a famous orator in ancient Greece. He was a stutterer since he was a child, and he was not fluent, so people laughed at him. Later, he practiced speaking every day with sand in his mouth, and finally established a very famous speaker. His situation is much more difficult than yours. Of course you can.