That’s pretty much it. I don’t think there are other ways.
Sorry for the tangent, but your post reminded me of Herodotus and his book “Histories”. If anyone reading this don’t know who that is, he’s called “The Father of History” for being the first (known) historian writing down events and history.
If you read his book, it’s full of “he said that, she mentioned this, I heard about, etc”. It’s an interesting experience compared to reading modern books, because modern books reference each other and won’t bother you with where they got that info in the text itself, they’ll just give you the sources at the bottom of the page or at the end of the book. Herodotus didn’t have that, he had to rely on what people said.
This resulted in some interesting accounts. For example, he talks about enormous “ants” that were about the size of foxes, lived in the hills, and carried away piles of sand that contained gold dust, which the locals collected and turned into wealth.
There’s some theories that he was likely talking about marmots, but we’ll never know for certainty. It may have been him just misinterpreting accounts, or maybe it was just someone who pulled his leg and he believed them.
Where I’m getting at, every book/article/etc we have is actually just writing down what someone else said/wrote with new insights. It’s easy to forget that nowadays with modern books and articles, “Histories” is a reminder of that fact.
Probably Kagi. Everyone that uses it swears by it, in my experience.
I tried it for a bit (until the free searches ran out), and it’s genuinely good. But I don’t use search engines enough to justify paying subscription.