maybeGroup always sorts by the group key:

Maybe there should be a way to turn this off if you want to render the groups in input order? It’s confusing because if you set the sort option to null, you don’t get input order, you get ascending natural order, which is different from most other cases. (It makes sense with the bin transform, though.)

Ref. https://talk.observablehq.com/t/facet-custom-sort/8002/6