If you’re in the US, you might see a new shaded section at the top of your Google Search results with a summary answering your inquiry, along with links for more information. That section, generated by Google’s generative AI technology, used to appear only if you’ve opted into the Search Generative Experience(SGE) in the Search Labs platform. Now, according to Search Engine Land, Google has started adding the experience on a “subset of queries, on a small percentage of search traffic in the US.” And that is why you could be getting Google’s experimental AI-generated section even if you haven’t switched it on.
SearXNG is great at what it does but it falls into the Bing/Google/etc-frontend category since it just forwards your query to one of the search engines it has modules for. It doesn’t have its own crawl and index.