For authors just look if they have published peer-reviewed papers and how often they are cited, or what their experience is (for example a journalist that was based in a foreign country for 2 decades could write just as well about an event as a historian might, but from a different point of view).

And for books I'd look at Wikipedia. For most popular books there is usually a Wikipedia page with a section that aggregates the book's reception by scholars with sources. For example:

https://en.wikipedia.org/wiki/Sapiens:_A_Brief_History_of_Humankind#Reception

https://en.wikipedia.org/wiki/The_Great_War_for_Civilisation#Reviews