Guys, please listen up here!
In normal windows NTFS filesystem, if you copy a 2GB file, it you would be using 2GB(original) + 2GB (duplicate)
However, in mac APFS filesystem, if you copy a 2GB file, it would be using 2GB(original) + 0GB (duplicate)
Yes, the duplicate takes ZERO GB. However, the actual size of the duplicated file is still 2GB, even though it takes up 0GB on the disk.
So yes!, a 512GB drive can hold 700GB & it's not an error on iOS or iPadOS.
Affinity Designer is duplicating tooo many files. It's a cache issue.
Trust me on this, I'm a developer myself, and I know what I'm talking about!