So sorry, the 1Z0-819 is a really tough exam. I think if there was more time it would be fair, but as you pointed out, speed and pacing are important. It helps on problems when you can "figure out" what they are asking for quickly. Like if have a lot of constructors in a question, look for obvious misuses of super() or this().
I'm glad you learned so much, that's the real purpose of certifications, to improve your education!