How long had the game been running when it crashed? If it was a very long time, that explains the loss of tech points and death of villagers. The game is saved only when you exit to the launcher or another app. If it crashes and you have to soft reset, Village Sim will revert to the last saved state and much of your progress can be lost when you start the game again.
As always, Arthur needs some details on the type of crash, and, if possible, what you were doing at the time in order to effectively find the bugs and fix them.