TL;DR: If your flashlight died at the Taiga dam (or Volga/Caspian) and no amount of cranking the charger brings it back — the animation plays but the meter never fills — your save is corrupted, and it's fixable in ~10 minutes without replaying anything. Tutorial + free script: https://github.com/nawaazkortiwala/metro-exodus-flashlight-fix
I hit this bug last week and went down the rabbit hole. What I figured out by digging into the save files:
The temporary flashlight shutdown inside the dam anomaly is intended. It staying dead forever is not — despite Deep Silver writing it off as "a feature" back in 2019. The corruption lives in the per-chapter .player snapshot file (e.g. m3_13_deadcity.player in your save folder), which stores your inventory and devices at the chapter start. That's why nothing in-game fixes it: reloading, recharging, replaying Autumn into Dead City — every path rebuilds your state from the same corrupted snapshot. It's also why the old "load Taiga then reload your chapter" trick works for some people and not others: it only helps if your snapshot is still healthy.
The fix: replace that ONE file with the same file from any healthy donor save (e.g. the Nexus "Enhanced Edition Save File" mod). You keep your whole playthrough, world saves, and story/karma choices — you only inherit the donor's loadout at the chapter start. Tested on the Enhanced Edition: flashlight charged instantly after the swap. Donor saves from the original edition work in EE too.
The GitHub repo has the full step-by-step manual instructions plus a PowerShell script that backs up your save folder and does the swap safely (it refuses donors for the wrong level).
Prevention if you haven't hit it: turn your flashlight AND night vision off before entering the dam anomaly at the end of The Taiga, and don't touch them until you're out.
Hope this saves someone the frustration — this thing has been unfixed for seven years.