Did you get the issue resolved? I am having the same issue with the Galaxy Tab S4. It started maybe 2-3 weeks ago. The tablet itself works fine, but the cameras, both front and back, are not working which affects facial recognition to unlock the tablet. I cleared the cache and data and rebooted it. The front camera then worked for facial recognition, but then the rear facing camera has the same issue. I have babied the device and in the almost 2 years I've had it, use it just a few times a month if that. I do check it's battery and make sure it gets charged and never sits completely empty. Just seems strange. It happened when I was using WhatsApp video in Secure Folder in the dark and all of a sudden the camera stopped working. I thought it was just the call, but noticed the problem has persisted. I have update the OS the front camera works intermittently the rear camera does not. I purchased an extended warranty, so will take it in again.