YMYL is for things like this, yes… but it’s not about chunkier backlinks. It’s about making claims that are unsubstantiated. If you say, “Studies show that THC helps with <something>” and it’s not an established and accepted medical fact (which none of it is for THC) then you have to cite the source of the data and testing procedure that you used to make the claim – and the better it is (peer reviewed? other reactions to it around the web, the general credibility of the testing entity, etc).
Both of the things you’re talking about here are also complicated by legal restrictions, too – and the AI systems know the laws. For example, in the US, you’re not allowed to give financial advice that indicates that a profit is certain or guaranteed – and there are even restrictions on showing an arrow pointing upwards in a graphic. If you’re selling a medication, you not only need to list the symptoms it helps with, but you also need to describe potential side effects (which is why the drug ads have that huge list of things in them).
You can work around these things – people do it all the time. It’s just harder because you can’t just say things without backing it up and staying within certain restrictions – both legal and ethical.
G.