It’s really tedious to do it manually and something like OpenCV shines.
We found a repo [1] with python code that automatically detects and blurs faces. This script was one of many, except it had a very high accuracy. Over 90%.
Removing exif data is a great idea.
[1] github.com/telesoho/faceblur
Python: https://gist.github.com/symisc/6ecdea76ba0d33d73ea7f23cade0d...
PHP: https://gist.github.com/symisc/d54808915093e5375fdcb841e4365...
Docs: https://pixlab.io/cmdls