db.Products.Include(x => x.ProductCategoryRelations)
.Include(x => x.ProductCategoryRelations.Select(c => c.Category))
.Include(x => x.ProductFileRelations)
.Include(x => x.ProductFileRelations.Select(c => c.File))
.Include(x => x.ProductPropertyRelations)
.Include(x => x.ProductPropertyRelations.Select(c => c.Property))
.Include(x => x.ProductColorRelations)
.Include(x => x.ProductColorRelations.Select(c => c.Color))
.Include(x => x.Brand)
.Where(predicate)
.ToListAsync();

1.Product
    2.Brand
        3.Product
            4.ProductCategoryRelations
                5.Product
                    .....
                    .....
                    .....
                    .....