It sounds like you're facing a formatting issue with text overflow when generating reports in languages with different character sets, specifically Chinese characters. Here are a few suggestions that may help:

Check the font: Make sure that the font you're using supports the characters you need for the specific language. Some fonts may not have certain characters, which can cause formatting issues.

Use auto-fit: Pptxgenjs has an option to automatically adjust the font size to fit the text within a cell. You can try using this option to prevent text overflow. You can find more information on how to use it in the pptxgenjs documentation.

Consider using a different library: While pptxgenjs is a popular library for generating PowerPoint reports, there are other libraries available that may better support multi-language reports. Some alternatives to consider include pptx.js, officegen, and docxtemplater.

Consider using a different format: If generating reports in different languages is a major requirement for your application, you may want to consider using a different format for your reports, such as HTML or PDF. These formats may provide more flexibility in terms of formatting and support for multi-language text.

Overall, it may take some trial and error to find the best solution for your specific use case. Good luck!