Ok yknow what actually,
What about a minecraft-esque voxel building game that emphatically does NOT have an infinite world?
With the explicit goal of being small and performant enough to just simulate the whole thing at all times. A little box of world to noodle around in.
Heck, do a Manifold Garden on it and have the world loop around in 3d!
That would much improve the issue of world borders and possibly add some very creative building possibilities.