There are a lot of options for finding duplicates. If you need one with a gui, I have used czkawka https://github.com/qarmin/czkawka
Honestly I have really enjoyed using Kdenlive and it has a nice browser, clip editor and library building system of edited clips and stuff.
https://docs.kdenlive.org/en/getting_started/quickstart.html#quickstart
Do you use kdenlive to get your files off your SD card to your machine or is it more for after you already have you files there? I've used kdenlive for just video editing before but didn't see any sort of importing tool that sorts files into directories like by date or anything like that
Oh I just learned that digikam can do audio so I think that solves what I need, will need to test further, and has import options hidden on the side tab that lets it auto create directories based on file extension and date
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