Freesound Forums

I've been looking for this sound for 8 years and recently it was used in "Atomic Heart"

Here's some examples:
https://youtu.be/XrBmvUROshU

This has been driving crazy.

I'm not sure what it is, but you can feed the audio from that vid to MVSep.com and separate the audio tracks to isolate the sound. That might give you a version of it that is high enough quality to use.

https://freesound.org/search/?q=flash+charging

Which sound?

Have you tried reaching out to Atomic Hearts directly?
They may be be able to get you in contact with the sound design team, granted not sure if they may be English speaking but it's worth a shot.