Super nice work!
I was wondering if the project can be expanded by supporting different geospatial indexing systems such as S2 and geotiles (bing).
I developed a common API to use them that can help support all those indexing systems.
The API more or less follows the H3 python API, so it shouldn't be that complicated to add support to other indexes.
If you fell like it is a good idea, I can open a PR with an experiment.