How about these two lenses, Sigma 24-70 and 17-70? What is suitable for shooting?

17-70 is better. But the price is expensive.

The image quality of the 17-70 is average, the workmanship is mid-range, the colors are bright, and it is suitable for general family photography. The deformity is well controlled at the wide-angle end, the mid-focus is stable, and the picture is clear, but the aperture is too small. It is a mid-to-low-end lens, and its image quality is better than that of the original kit lens, but not as good as that of the original lens of the same grade and focal length. There are many comparison articles with Nikon 18-70 on the Internet, you can refer to them.

It is recommended to buy Tamron AF17-50mm F/2.8 XR Di II LD Aspherical [IF]. This head has a constant large aperture of 2.8, the image is much better than the Sigma 17-70, and there is room for value preservation