They are both fine pics, but viewing them both here on my big 4k monitor/screen, the iPhone 7 example shot there is actually quite a bit sharper and has more detail in the rear of the picture. The S8 picture the fence, leaves on the climbing plant and the background objects are quite blurry. Indeed the strawberry pot which is clear in the iPhone shot looks more like a halloween pumpkin on the S8.
Are you sure your camera sensor on the S8 hasn't got fingerprint grease on it perhaps resulting in the blurrier shot ?
Well the only thing I clicked was auto adjust on the picture
Here's another pic comparison
7 plus
S8 plus