I didn’t even know about the tool “Easily missed” (https://forum.inaturalist.org/t/a-tool-to-help-you-fill-local-data-gaps-easily-missed/37575), and it is actually pretty much the thing I had in mind. I will have to try it out some time to see if it works as I imagine it. For me it would be important that the highest scoring species disappears after it has been filled within a cell (or rectangle or radius), because in that case the data density (or observation density per area) would be sufficient.