Get all files in all folders and sub folders of a SharePoint online document library recursively using CSOM and CAML

GetAllListItems.cs

        private List<ListItem> GetAllItems( ClientContext Context, List list, List<ListItem>  ListItems)
        {
         
            camlQuery.ViewXml =
@"< View Scope = 'RecursiveAll'>
    < Query >
        <Where>
      </Where>
        <OrderBy>
            <FieldRef Name='ID' />
        </OrderBy>
    </ Query >
</ View >";

            ListItemCollection AllItems = list.GetItems(camlQuery);
            Context.Load(AllItems);
            Context.ExecuteQuery();
            foreach (ListItem item in AllItems)
            {
                if (item.FileSystemObjectType == FileSystemObjectType.File)
                {
                    if(!ListItems.Contains(item))
                        ListItems.Add(item);
                }

                if (item.FileSystemObjectType == FileSystemObjectType.Folder)
                {
                    camlQuery.FolderServerRelativeUrl = item.FieldValues["FileRef"].ToString();
                    GetAllItems(Context, list, ListItems);
                }
            }
                
            return ListItems;
        }