It’s a shame, for potential observers but also as some local expertise is missing for many taxa (of course there are some great IDers already). As @fffffffff suggested, there are some local alternatives that cover parts of what iNat offers (e.g. there’s a pretty decent bird ID program, a bit like the computer vision model of iNat) though I’ve not come across anything that combines most of what iNat offers.
In terms of the app, it isn’t on any mainland Chinese app store I’ve seen. It probably wouldn’t get on any store (even if it didn’t use Google Maps) because the maps would have to conform to very precise specifications and there would be questions raised about naming and descriptions of places.
I think there’d be hope for the website version if OSM or similar were a back-up map. See thread here for more discussion on this point: https://forum.inaturalist.org/t/use-openstreetmap-maps/2588.