After unsuccessfully searching for a teardown walkthrough I decided to make my own.
I'll walk you through disassembly and reassembly of a Ubiquiti Unifi Cloud Key Gen2 Plus.
Have you dealt with a corrupt unit or having issues with improper shut down when the device loses power?
It's most likely the internal battery.
With a few simple tools and about 30 minutes of your time you'll have your CKG2+ back up and running like new.