Two paths into historical reading
Authorized nonfiction biography, or well-researched historical fiction. Both work. Most serious history readers read across both. These picks are organized by the two paths.
For the authorized-biography reader
Bill Clinton's My Life is the modern primary source. James R. Hansen's First Man is the authorized Armstrong biography (and the source for the 2018 Chazelle film). Both are long. Both reward the long form.
For the technology-history reader
Katie Hafner's Where Wizards Stay Up Late is the standard reference on ARPANET and the origins of the internet. Cyberpunk (also Hafner, with John Markoff) is the 1991 longform account of three early hackers (Mitnick, Pengo, Morris) that helped define the public understanding of hacker mythology.
For the historical-fiction reader
Boris Akunin's The Winter Queen (1876 Moscow). Clive Cussler's Isaac Bell novels (1906-1907 America: The Chase, The Wrecker). Rennie Airth's John Madden series (interwar England: River of Darkness). Kerry Greenwood's Phryne Fisher (1920s Melbourne). Each is researched with the kind of care that allows fiction to do real history work.
For the post-WWI specifically
Rennie Airth's River of Darkness is the best contemporary novel about the post-WWI English shell-shocked-officer-turned-detective. The Madden series carries this through five novels over roughly two decades. For readers of Sebastian Faulks's Birdsong, this is the natural next stop.