25mA doesn't heat up the LED, but it's only enough to see contours a little bit better in the dark, or to read a text while lighting it from 30 cm distance. It's barely usable if you want to light up your path in the night - you can simply trip over something because youre walking and the flashlight is weak (I did, my eyes couldn't see a wire - it had low "special" contrast to background and it just blended in and became a part of a "noise", idk).

It's like a torch app on Galaxy Watch - helps you to see something a little bit better, but in case with watches, it's the best they can offer, while flashlight on Xperia is brighter than watches' screen, yet somehow not better + you have to hold the phone in your hands.

Sony could increase it's brightness to not be so far behind competitors or implement brightness slider with a warning notice with approximate time recommended for each brightness level. It could be accessible by long tap on flashlight quick settings tile.

I think every Xperia phone has a custom mod that increases flash led's brightness now, but Sony keeps setting it to lowest possible with no option to make it brighter, making it the weakest among others and sometimes even kind of dangerous (you can't trust it but you have no other choice)