The Meta tab has an export button if you're concerned with maintaining state, but it should save after virtually every operation. What sort of data have you lost? It'd be worth looking into on my side.
The projects. I completed 2 out of 3 steps of the water purification system and then closed the game without doing anything else. When i came back the two steps were undone and all the stamina i spent on it was returned, meaning it saved at no point during the first or second step.
Projects specifically have been a problem point in the past. I'll take a more in-depth look at the save structure and figure out what the problem there is. And I've added a backlog item for a manual save button. Even if everything works flawlessly there's no reason not to give you one.
The issue was both larger than I thought and easier to fix. New version is out with both the button and projects now autosaving every step of progress properly.
