So looks like according the stack overflow link from @hades above, your files are individually encrypted. Based on the solution comment, there should be a .MetaEcfsFile with the Samsung file encryption metadata in the SD card root directory if this is true. If so, you would likely need to plug the SD card into a Samsung phone (unclear if it needs to be original phone, same model, or just Samsung in general) and use the “Biometrics and security” menu to hopefully decrypt the SD card. If you still have a newer Samsung galaxy, I’d try with that one first before attempting to locate an older model. And if that doesn’t work, it might require the original phone. Backup SD before doing any of this.