So many topics about this issue! This one https://forum.inaturalist.org/t/an-abundance-of-duplicate-observation-flags/32582/15 contains a staff comment by @tiwane advising not to use the DQA section for duplicates.
“There is currently no DQA vote to address duplicates. Please don’t use a DQA vote for them. My comment was saying perhaps there should be, but right now none of them address the ‘problem’ of duplicate observaitons.”