Returning Data From Tables Having Many To Many Relationships C# LINQ .NET (Dot Net)

public async Task<IEnumerable<Object>> GetBooksAsync(int pageNumber, int length = 0)
        {

            // get all the books needed to send to user
            return await _context.Bookss
                    .Skip((pageNumber - 1) * _options.ItemsPerPage)
                    .Take(_options.ItemsPerPage)
                    .Include(book => book.BookAuthorss)
                        .ThenInclude(bookAuthor => bookAuthor.Author)
                    .Select(books => new
                    {
                        books.Id,
                        books.Title,
                        Authors = books.BookAuthorss.Select(author => new { Id = author.Author.Id, author.Author.Name }),
                        booksCategories = books.BooksCategories.Select(category => new { Id = category.Category.Id, category.Category.CategoryName })
                    })
                    .ToListAsync();
        }