Purely subjective to be honest, low light, sensor size, focal length blah blah.
Personally I see the iPhone as having the the Swiss army knife of cameras, great in all situations but not the best main camera, uw or telephoto available to day. You'd be looking at the latest and the last few generations of Chinese phones, Huawei Pura's, Vivo, Oppo, xiaomi etc, last year's 35mm Nubia is a damn good main lens too but the overall package less so.
However, you really can't go wrong with the iPhone camera and of course the best camera doesn't necessarily mean the best photo/image. Post processing plays a big role these days as well as the photographer of course.