Isn't searx what you're describing? I was running an instance for a while, and it's basically a meta search engine that has support for all kinds of providers.
There are also some web extensions available so that you can fill it with more data.
There are also some web extensions available so that you can fill it with more data.
> a decentralized p2p websearch and collaborative tool.
> It relies on a distributed collaborative filter[6] to let users personalize and share their preferred results on a search.
For me it made more of an enterprise-grade use case (e.g. for building a search for your own file servers or confluence) so I only tested it out a little. It's a huge java project, that's why I decided to go with searx back then...cause yacy was pretty hard to setup.