As an SEO I've watched this downfall in real time and it's sooooo bad,

First we accepted rich snippets and instant answers stopping user click-through Then they expanded adds above the fold Then YouTube links started to outrank content

and we sort of found our way around that, people who wanted more than a one line answer still clicked through so if you sold a product, you could still make revenue with a more serious user clicking through, but ad revenue and affiliate sites took a knock and many died

But i'd say in the last 2 years its really gone down hill faster, Googl wasn't prepared for ChatGPT and spammers took full advantage, they would copy pasta sites and use LLMs to paraphrase and post content, spinning up huge sites that would steal traffic.

Google had to patch

Then they did the same thing, but but bought expired domains that had a previous history

Google had to patch

Then they bought subdomains on popular sites (domain reputation abuse) and spammed it

Google is still busy patching it

As for the HCU and YMYL shit, that's all biased towards big business and big sites, niche sites are getting creamed and even if you are a good quality content niche site, Reddit, linkedin pulse and quora posts about your post outranks you

I've been using qwant mostly for personal searches, it reminds me of google 10 years ago in terms of search relevancy