I can tell you from experience that everyday users don‘t care that much about seeing ads. Some even like them. They care even less about the possibility of manipulated results. It’s also a really big topic to explain.

Besides the question of the funding of this hypothetical search engine. It being „fair and objective“ or even completely transparent about its ranking, would mean it‘d be SEO‘d into oblivion by everything from click/content farms to trolls to more nefarious actors. As long as many on the internet want to make money or manipulate people somehow it‘s not really doable in my opinion.