Help me to solve my idea. What instrument i need to use?

Hello community!

I’m a beginner developer, and I would like to ask a few questions. The idea of my project is to create a bot that can respond to users based on my knowledge base. I have JSON files, totaling about 2GB, containing information objects about products.
example of my json file

[{"name":"microvawe sku 2312", "param1":"value1"},{"name":"phone 32/64", "param2":"value2"}]

I need the bot to, in response to a user’s request:

  1. What are the specifications of the microwave (not an exact match with the name) - to give an answer from the database
  2. What is the cost of the phone product?

I connected the Assistant API and the GPT-4 model, but I encountered a problem with very slow responses. In one case, the bot found the answer, in another - it found it. The behavior is unstable.

Dear community, could you advise which tool would be better to use? Should I use function calling and perform a separate search through my files?