I would say that there isn't currently a "best alternative" but rather there is a small group of alternatives that each seem to have "use cases" as it were (shocker, kind of how it used to be in the 90s/00s before Google dominance). But even from person to person, people disagree on what the best use case for each is.

There's some focused more on "privacy" like DuckDuckGo and searX.

I've heard Bing has pretty good results for anything AI related for all Microsoft's investment in OpenAI.

I've heard good things about Qwant for music searches.

Someone else here in this thread just brought up Mojeek, which is supposed to be also privacy focused but includes searching by "emotion."

Presearch is decentralized, but I haven't looked "under the hood" of how its decentralization works.

Startpage is Google search results but behind a proxy so Google isn't getting your info when you search.

I mean, it seems like there's a lot of decent alternatives. I wouldn't be surprised if what's left of the shell of Yahoo! started investing in trying to outperform Google at this point.