I fought for the DQA for Single Subject.
There are open request for Duplicates. Going back years.
You can make a feature request. Checksum has been suggested.
https://forum.inaturalist.org/t/curator-guide-policy-on-duplicate-flags-lets-change-it/62066
https://forum.inaturalist.org/t/duplicate-prevention-notify-observers-if-their-image-checksums-match-others-on-the-site/258
From Feb 2019 with 103 votes. We Have A Problem, we have an issue with duplicates.
Some identifiers are happy to ID duplicates. Not me. A new Duplicates DQA that pushed to Casual would work for me. iNat is too big to say that, and that, and that, are not a problem.