What is the issue?
I also have a copied of the data on my Mac.
If you have a copy of the data, you best move on and create another backup of this data.
If you have another copy of the data, what is your worry? To recover the data on the flash data, you would need to contact specialists in data recovery. This will not be cheap. One of the best in the business is drivesavers.com. You can give them a call and see what opinion they have on your situation. You will need a dump truck worth of pennies or more.
This is controversial around these parts, but I recommend you get your photos out of the Apple ecosystem and store them as one photo per file on multiple external storage devices. For long term storage, don't rely on usb memory sticks nor external ssd drives. LoC does not have data on the reliability of usb memory sticks. Apple seems to be saying do not store photos on external ssd drives. One device should be off site. Using a cloud service is fine. Remember a lot of cloud services are sync services. That is should the file be deleted on the local device, the photo will be deleted in the cloud. For this reason, I never install the cloud service software on my computer. I use only file upload. For those who complain, my assessment is that the apple Eco-system doesn't match Library of Congress's requirements for digital archiving.
informative video:
Archiving Digital Photos - Multimedia - Digital Preservation (Library of Congress)
printed version
Digital Photos - Personal Archiving | Digital Preservation - Library of Congress
General information on digital preservation:
Personal Digital Archiving | Digital Preservation - Library of Congress
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