There is a domain available in the .net zone that consists of two words and 15 letters, which perfectly represents the concept of my project. However, the domain used to belong to a Chinese online store with 3,000 pages in Google's index.

 I am hesitant to take this domain as I am unsure if it is the right choice. Another option is a single word, five-letter domain in the .biz zone that also reflects my idea, but may not be as aesthetically pleasing, for example, zcredit.biz. I am uncertain about what to do as I want to avoid making mistakes when choosing a domain for my large-scale project.

Based on my experience, domain history can be uncertain and problematic.
Therefore, it would be best for me to choose a new domain that has no prior history. If I find it difficult to come up with a suitable name, I should consider exploring other options.

I would not take a domain with a bad or inappropriate history. Bad karma has never helped anyone.