UsAsk HN: What should I use to build UI interface for an LLM

I want to create an LLM UI interface for my fine-tuned Llama model, similar to a private GPT chat. The interface should allow me to upload multiple documents, add prompts to them, capture the response, and format it with Markdown tags based on one of the attached template documents. What should I use? Preferably something open-source so I can customize it. What do you recommend? I looked at Gradio, but it seems too “modest,” and OpenWebUI is too complex and extensive. I would also like the solution to support PWA technology.