without knowing exactly what you’re describing, i would just suggest that you’re making sure you’re making the distinction between verifiable and non-verifiable observations.
there is one very prolific bird observer who records almost exclusively observations without photos. so none of those observations are consdered verifiable. if you search verifiable observations only, you won’t find the bulk of their observaitons.
also note that there is currently an issue with the way the verifiable filter is retained in the Explore page: https://forum.inaturalist.org/t/status-of-verifiable-checkbox-does-not-persist-across-species-links/55852.