I keep wondering all the time why torrent search is based on websites (centralized), which can be taken down, etc., while once you have a torrent file or a magnet/hash everything is distributed.

Is there a main reason why there isn't (AFAIK, even though I haven't really researched) a distributed search that wouldn't have these problems? Is it a tech problem that literally can't be solved? Or it just hasn't been done? It seems like search is the obvious weak link, since the websites keep disappearing or taken down or blocked by governments and ISPs, etc.

You can't build a decentralized search because there's no way to trust whatever results you get until you actually build it. If you don't want to rely on a specific community, your best bet is to crawl yourself and search locally: you can do that with magnetico (https://github.com/boramalper/magnetico/). Don't be frightened by the fact that it is archived, it works.

The problem then will be, how do you make sure your content is legit? There's no magic way here, the best thing you can do is compare the number of seeders and aim for the highest. If a torrent is fake, people will delete it and it won't be seeded. I have a thingy for that: https://sr.ht/~rakoo/magneticos/

The problem then becomes, number of seeders naturally selects towards popular content. It doesn't ensure viability of content. But I don't think there's a technical answer to that.