yes we are indeed a standalone, the sizes of bubbles are reflections of the number of index-usage relationships yep is attached to ahrefs: https://techcrunch.com/2022/06/03/yep-search-engine/ where I can speak to where results come from, I couldn’t tell you about their model
sorry for taking a while to get back but the main source of mojeek revenue is api sales, having people pay to access results for different applications (bing does similar i.e. duckduckgo, qwant, ecosia)