Are you taking duplicate photos via your drone? If you have DNG and jpeg selected or any combination there of selected, you're going to be taking dups but the extensions will be different. For example, I've seen DJI001.jpeg and DJI001.dng The actual images are different sizes too (slightly) but the file names are the same.
Good idea, 95% of people like to find solutions on Google if they don't know what to do,because you are asking how do you find them quickly, if you find these duplicate photos one by one, it will takes a long time.
A quick way: How to Quickly Find and Delete Duplicate Photos on a Mac
Are you taking duplicate photos via your drone? If you have DNG and jpeg selected or any combination there of selected, you're going to be taking dups but the extensions will be different. For example, I've seen DJI001.jpeg and DJI001.dng The actual images are different sizes too (slightly) but the file names are the same.