"Best smartphone camera" sounds like "best British food" or "best beach in Greenland". Smartphone cameras got better over time, but they seriously lack behind real cameras. They apply some software "magic", but you can do the same with images from real cameras. Taking a photo with a smartphone camera is like running a marathon with Birkenstock sandals. Possible, but not recommendable.
Camaras aren't the least interesting things on a phone, but for me, they are pretty far down the list. They are definitely not a reason to upgrade.