Hello, I don't know if you can understand Chinese, so I will attach an English version to my above reply according to your locale.
First of all, thank you for your attention to the ethnic languages used in China's minority ethnic autonomous regions. But it is necessary to remind you that whether to use bilingual annotations in ethnic minority autonomous regions, and to what extent, is a very controversial issue with divided opinions among China community's local editors. You can read https://wiki.openstreetmap.org/wiki/Talk:%E5%B0%91%E6%95%B0%E6%B0%91%E6%97%8F%E5%9C%B0%E5%8C%BA%E8%AF%AD%E8%A8%80%E6%96%87%E5%AD%97%E6%A0%87%E6%B3%A8%E6%96%B9%E6%A1%88 to find out more about it. Looks like this debate can last for years, and I don't recommend making large-scale modification until the local community has settled on a final solution. It is currently generally considered acceptable to use bilingual labels in city names.
As a member of China's local community, I have also communicated with mappers living in Guangxi. In fact, in Guangxi, the lingua franca is only Chinese, and the existence of Zhuang language is basically not seen in daily life. It only appears as a symbol in official documents. This is different from Xinjiang, Tibet, and Inner Mongolia where ethnic languages are still widely used.
China legally divides 56 ethnic groups (Han and 55 ethnic minorities), the Hui do not have their own ethnic language, so theoretically there should be 54 ethnic languages - but only Uyghur, Tibetan, and traditional Mongolian are the only languages that are active and widely used in daily life in provincial administrative divisions.
Therefore, I do not recommend that you use bilingual tagging in Guangxi, or at least you should try to communicate with some mappers living in Guangxi before conduct such modification.

Thank you.

Best Regard. 顺颂时祺