why do i get a nil value even if i give a url variable a value?

This seems to be an issue caused by downloadFile making an asynchronous call, I am not sure exactly why it doesn’t work but I managed to get it to work with the below solution where I skipped the completion handler and assigned the documentsUrl property inside the URLSession closure instead

So the do clause is changed to

do {
    try FileManager.default.copyItem(at: localURL!, to: destinationPath)
    documentUrl = destinationPath
}

To make the UI clearer I added a disabled operator to the second button so you can’t click it until the file has been downloaded

Button("Open PDFView") {
    ispresented.toggle()
}.disabled(documentUrl == nil)

Note that you can of course keep the closure if you want to do other stuff there but it wasn’t needed for this solution