The Nothing Phone (1) has an aluminum frame sandwiched between two panes of Gorilla Glass 5. Does that mean that the front and back are equally resilient to falls? It turns out that they are not, as you can see in the PBKreviews drop test in the video below.
The phone comes with a plastic screen protector out of the box and that was kept in place for the test – it may be what made the difference between cracking from waist height and surviving after being dropped.
For better protection of the back you can use the official protective case, which is transparent so that the Glyph lights can still do their job. The back of the phone is flat, so you could stick a protector on there too, if you don’t want the extra bulk of the case.