In my hands the iPhone 12 consistently performs better in indoor conditions than my old a5100 (basically a more compact a6000), especially with the awful kit lens.

I like shooting outdoor on telephoto (135mm+), and there the phones are nowhere as competitive, and won’t be for a long time, if ever. Actually that’s where the progress in standalone cameras is: more compact telephoto lenses, sharper zooms, faster autofocus, even less noise. And no, multiframe fusion won’t help when you’re shooting quick action.