The Redmi Note 10S is yet another smartphone from Xiaomi in the crowded Redmi Note 10 series. This one is being launched in India amidst three other Redmi Note 10 models, including the Redmi Note 10, the Redmi Note 10 Pro, and the Redmi Note 10 Pro Max.
The Redmi Note 10S sits between the Redmi Note 10 and the Redmi Note 10 Pro, being largely identical to the Redmi Note 10 but with a better camera and chipset on paper. It is, however, closer to the Redmi Note 10 Pro in price than the Redmi Note 10, so that camera and chipset better be good to make you want to buy this phone instead of just getting the Pro model. But then again, that may be the plan.
The Redmi Note 10S is also the first phone in India to launch with MIUI 12.5 out of the box. Xiaomi is calling this an "interim" version of 12.5, which means it lacks some of the features of the final release but we will just have to see about that.
The retail box isn't special by any means. It contains the usual user manuals, a USB-A to USB-C cable for data transfer and charging, a transparent silicone case, which is pretty hard to put on and remove, and a charging brick rated at 33W.
A LineageOS release exists for this one.
10 Pro is definitely the better one, as it has better hardware.
Might be just reading mode. Should be a shortcut from Quick Settings (drag down from top) or can access it via normal Settings.