jnd,
Um not really, starting with a jpeg those adjustments are much much more constrained than if you can start with a raw.
iPhones shoot to jpeg, not really good jpegs either unlike the Fuji XT1. Nor do iPhones shoot directly to tiff, but wait only a few Nikons do that.
So no, raw shooting, combined with good raw extraction software, is how to have much better control of the following: noise, WB, exposure, tint, optical compensation.
Direct capture to jpeg allows for little adjustment to any of those things, before things go really wrong.
Started out doing photography at the age of 6 using an uncle's old 1940 kodak brownie box camera. At 15 years of age, I decided to buy my very own 1975 Praktica SLR camera. I now shoot with a Nikon D850. I do unpaid TFP and commercial paid work.