See this thread for a discussion (about 9 months old):
https://forum.inaturalist.org/t/inaturalist-user-trends-with-r/12538
In general, rinat is outdated, using only the v1 iNat API. It is still being (slowly) worked on at ropensci (https://github.com/ropensci/rinat). In general, if you are wanting to do biodiversity work with iNat data, working with the data exported to GBIF via GBIF tools (e.g., rgbif) which are better developed and maintained.