The only limitation on a drive formatted as FAT32 is no single file can exceed 4GB in size.
So you can copy all files over to that Micro SD card provided all individual files are less than 4GB in size.
To ensure the process goes smoothly, you should copy over the data in small amount, not the full 700GB in one go.
Also, it is very important, never use the Move option in File Explorer, because if that process goes wrong, you will lose the files, always use Copy and Paste, then once the files are in the new location, you can delete them from the original location.