Considering the critical nature of the errors I discovered, I feel I deserve some form of a reward. Reasonably speaking, what kind of reward do you think I could ask for?
You didn't report a security vulnerability in the app, so you are not entitled to any pay.
Bug reports like the one you just reported are almost never covered in buy bounty programs. [then again, this would be a different story if you did this as part of AWS Bugbust program of something similar.]