1. Civillizational collapse seems to me a straightforward answer (and a sort of neglected field in History).

2. Maybe I didn't understand the question properly, or it's just that "historical work" is vague and ambiguous... Would you say Acemoglu's Why nations fail is historical research? Or Melissa Dell's paper on Peruvian Mita?
Since our judgments often derive from past data, then in a trivial sense you could call it all "historical work" that is "action-guiding". But when it uses, e.g., GDP data, we usually call it "Economics"... and it's not just because social sciences are messy: e.g., Harari begins Sapiens by saying something like "Physics is the history of the Universe".
One possible way to precisify "historical research" is to limit its reference to something like "research on facts that ocurred more than 25 (or 50? or 10?) years ago using methodologies deployed by historians". In this case, i think the point of the question would be less "is studying history useful for EA?" and more "is what historians do useful for EAs?"

Here is a long answer I wrote a while ago. Not sure how action guiding they were but I am glad the work I mentioned was done.

https://forum.effectivealtruism.org/posts/uH4kGL4LgQdCgMpDP/can-we-influence-the-values-of-our-descendants?commentId=Wey6Q2KBELrK3n5BW

The relevant part:

Do you have any ideas about how to make progress on [studying the cultural legacy of intentional movements]?

There is a large corpus of historical analysis studying social movements like the suffragettes or the slavery abolitionists. My bet is that there would be large value in summarizing their learnings and taking an "eagle's-eye view" to look for interesting patterns in this movements. How long did it take since the movement was conceived until it spread? How did the main ideas originate? Can we build "infection models" of cultural ideas, making retrospective predictions of eg how many people supported LGBTQ+ rights each year? My outsider perspective is that there is very few people / teams working on the intersection of qualitative analysis and history of social movement, so I expect plenty of low hanging fruit there.

Within the community there has already been some work on summarizing historical movements. For example, Nuño Sempere talked about the Spanish Enlightment and General Semantics here, Holden Karnofski summarized ALL HISTORY here and Alex Hill and I wrote about the history of women's rights and animal rights here. I would like to see more work on this vein, and more actual historians participating in the community.

Snodin and Kinniment's research on succesful technological fields is also relevant, as an example of the kind of history-flavored, "eagle's-eye view" research I think the EA community can excel at.

Regarding specific movements I would personally be interested in studying more closely: animal rights, feminism, the abolition of slavery, the Enlightment, the Scientific revolution, nazism, major religions and Russell's rationalism are easy examples of cultural movements that became widely successful at some point and will be good to look at from an "eagle's-eye view" perspective. Finding failed social movements to study is harder, though identifying a collection of them would be a great project for an early career researcher.