For non mathematical topics "John Von Neumann: The Scientific Genius Who Pioneered the Modern Computer, Game Theory, Nuclear Deterrence, and Much More" by Macrae is reasonably well sourced although the author's self admitted lack of mathematics does show. A biography reasonably covering mathematical topics too doesn't really exist yet given the wide range of von Neumann's work but if you're more interested in mathematical legacy there was an AMS symposium on him in 1988 whose proceedings are available online https://bookstore.ams.org/pspum-50 and other various smaller papers on his technical legacy over the years.

A short one can be found in The Computer And The Brain written by his wife as foreword. https://yalebooks.yale.edu/book/9780300181111/computer-and-b...

I found "John von Neumann and Norbert Wiener: From Mathematics to the Technologies of Life and Death" excellent, if you don't mind learning about Norbert Wiener as well :).

There's a fairly old book by William Poundstone "Prisoner's Dilemma: John von Neumann, Game Theory, and the Puzzle of the Bomb". I can't vouch for it, as I read it long ago and don't remember just how much of a biography it was. It's very readable though.

Turing's Cathedral has a lot about Neumann

I can recommend the one published by the AMS.

Prisoner's Dilemma

There aren't any, though there's a new one coming out very soon which might be good.