How do I collect more stars on Wadirum?

I was having this same problem and I think I found the solution, as much as you'll prob hate to hear this there is prob land you haven't built yet. I was looking around hopelessly and I found a section I hadn't built out on and the two were just out on about 4 or 5 tiles I had forgotten to build. Hopefully that's the problem and you can get them to work the elevator

Once I got to the point where I couldn’t progress any farther I closed and reopened the game and the stars magically appeared on land I had already unlocked. I have no idea why.

Most of the stars are not in the caves. They are in random cells as you expand the land area. There is a spreadsheet I found on Redit that lists everything by cell on Waridom. It's great!!

Once you start unlocking land for the rest of the map they will be in the middle of some of them