I'm not sure what percentage of the results are Bing (perhaps the majority), but I think it's inaccurate to say that Kagi is just Bing under the hood:
> Our searching includes anonymized requests to traditional search indexes like Google and Bing and vertical sources like Wikipedia, DeepL, and other APIs. We also have our own non-commercial index (Teclis), news index (TinyGem), and an AI for instant answers.