Anyone stumbling on this thread: A man from the future - ananyo bhattacharya chronicles his life and it is thrilling. If anyone has any of the questions the OP has, the book explains them. There were plenty of open problems then, they just were so unexplored it looked like he and hilbert invented them.

Word of caution, relative to most of you folks I am a mathematical toddler. The book may be overly simple but my calculus professor really enjoyed it.