DxO is not at all reliable for phones and their rating is BS. They rated iphone 5s above lumia 1020. EPIC FACEPALM.
Galaxy s5 has much much better video recording both at 1080p and 4K and it just crushes any other smartphone in video in detail levels, dynamic range and contrast. Even z2 and g3 pale against s5 in video recording.
Regarding photos, s5 is the best android phone for daylight photography, panoramas( 60 MP panoramas) and HDR. It also has insanely fast autofocus with hybrid AF. The low light camera quality is bad in auto mode but turn on the stabilization mode along with HDR and you'll get very usable pics which match z2.
All in all, DxOmark is useless but s5 is a very capable camera.