Import/parse local .json file works in Simulator, but on device "The requested URL was not found on this server."

I've been struggling with this for a few days, and hoping someone can point me in the right direction.

I'm using a Document Picker to import a .json file into my app from the Files Directory. On the simulator everything works great, but when testing on a device I keep running into NSURLErrorDomain Code=-1100 "The requested URL was not found on this server." (I've also tried the alternate approach of using .fileImporter, only to get the exact same results.)

I'm probably missing a permission or something? I can't seem to find the right answer online. I do have Supports opening documents in place & Application supports iTunes file sharing in the plist.

Any suggestions would be appreciated.

Here's my code that's mostly cobbled together from tutorials, forums, and anywhere else I could find.

import SwiftUI
import Foundation
import MobileCoreServices
import UniformTypeIdentifiers

struct DocumentPicker: UIViewControllerRepresentable {
    func makeCoordinator() -> DocumentPicker.Coordinator {
        return DocumentPicker.Coordinator(parent1: self)
    }

// Document Picker Setup
    func makeUIViewController(context:  UIViewControllerRepresentableContext<DocumentPicker>) -> UIDocumentPickerViewController {
    let supportedTypes: [UTType] = [UTType.json]
    let picker = UIDocumentPickerViewController(forOpeningContentTypes: supportedTypes)
        picker.allowsMultipleSelection = false
        picker.delegate = context.coordinator
        return picker
    }

    func updateUIViewController(_ uiViewController: UIDocumentPickerViewController, context: UIViewControllerRepresentableContext<DocumentPicker>) {
    }
    class Coordinator: NSObject, UIDocumentPickerDelegate {
        var parent: DocumentPicker
        init(parent1: DocumentPicker) {
         parent = parent1 }

// getting the url for .json
    func documentPicker(_ controller: UIDocumentPickerViewController, didPickDocumentsAt urls: [URL]) {
        guard let archiveurl = urls.first else {
            return
        }
        URLSession.shared.dataTask(with: archiveurl) { data, response, error in
                if let data = data {
                    let jsonDecoder = JSONDecoder()
                    if let JSONdecoded = try? jsonDecoder.decode(Jproject.self, from: data) {

// using the parsed .json data to populate app info..
                        self.parseJproject(parsedJSON: JSONdecoded)
                    }
                    return
                }
            }.resume()

        }