Move files from applicationStorage to Documents in app - actionscript-3

Question

I've got an app that, since 5 years now, that displays an offline map by reading from a folder embed in it ("assets").
Since Android 11, it's impossible to read from ApplicationStorage (Error #3001: File or directory access denied), so I'm trying to copy the folder from applicationStorage to "Documents".
What I did :
source = File.applicationDirectory.resolvePath("assets/maps");
destination = File.documentsDirectory.resolvePath("Documents/www");
source.addEventListener(Event.COMPLETE, onMapCopyComplete);
source.copyToAsync(destination, false);
function onMapCopyComplete(e: Event): void {
source.removeEventListener(Event.COMPLETE, onMapCopyComplete);
log("onMapCopyComplete()");
}
I've got a return onMapCopyComplete() but when I'm looking in InternalStorage/Documents of my phone I've got the folders but all are empty... None of the files were copy..
PrintScreen computer vs phone
To read the files, here's what I'm doing :
function startMapsView()
{
var indexFile:File = File.applicationStorageDirectory.resolvePath("www/index.html");
if (!indexFile.exists)
{
log("startMapsView() Index file not found, Please check www/index.html");
return;
}
// Create StageWebView
stageWebView = new StageWebView(isMobile); // Set to TRUE for System's NativeWebView, FALSE is for AIR's WebView
stageWebView.stage = stage;
stageWebView.viewPort = new Rectangle(0, iOSStatusBarHeight + headerBarHeight, deviceStageSize.width, deviceStageSize.height - (iOSStatusBarHeight + headerBarHeight + footerBarHeight));
stageWebView.addEventListener(flash.events.Event.COMPLETE, onStageWebViewLoaded);
stageWebView.addEventListener(flash.events.ErrorEvent.ERROR, onStageWebViewError);
stageWebView.addEventListener(LocationChangeEvent.LOCATION_CHANGING, onStageWebViewLocationChanging);
// Load Map URL
stageWebView.loadURL(mapsURL);
}
And mapsURL is define by :
function setMapsURL(doNotEnableButtons: Boolean = false): void {
var indexFile: File = File.documentsDirectory.resolvePath("Documents/www/index.html");
trace("indexFile url is = "+indexFile.url);
if (!indexFile.exists) {
log("setMapsURL() Index file not found, Please check www/index.html");
return;
}
var assetsDir: File;
if (!useOnlineMaps) {
assetsDir = new File(destination.resolvePath("index.html").nativePath);
} else {
assetsDir = new File(destination.resolvePath("onlineMaps.html").nativePath);
mySavedData.data.onlineMapChoosen = false;
}
mapsURL = assetsDir.url;
log("setMapsURL() " + mapsURL);
if (!doNotEnableButtons) enableMapButtons();
}