A few years ago, I investigated if there is a business opportunity in quality search.

The biggest hurdle I found no way around is the content. Not all but a lot of high-quality information is paid. You get access to it as a user but not if you want to index it as a platform. And you need a lot of different providers to have good coverage. That might get easier if you have lots of users, but you do not get users without content. The platform chicken-egg problem.

Profitable niches like Bloomberg’s business information definitively exist but this would not be the high-quality generic search engine you described.