Hexagons.
There's a library available at https://github.com/uber/h3 that lets you partition the earth into hexagons (minus the required 12 pentagons) at various resolutions. It's spiffy. I had the hardest (read impossible) time when I first took a look at it getting it to compile into a mobile game. It worked fine in desktop, but not on mobile.
So I punted and converted the whole thing into C#. It's a hot mess currently, but it works.
However, the folks who created H3 added functionality and some optimizations that I want, so I'm rebuilding it, partly with dealing with some of the issues that have come up with my game during development. It's coming along smoothly, though the unit tests are what's slowing me down at this moment.
Once that's done, I'm going back to my game. Covering the world in brightly colored hexagons as reality starts to crumble around you.
So, still... Hexagons. That's what I'm working on.