UNSOLVED Bottleneck on DATABASE
Have you already moved the mysql server (service) to its own server instance and not running directly on the FOG server?
Is the disk where the database stored been moved to a flash based media (SSD or NVMe)?
Have you run the mysqltuner script against your mysql server? Have you implemented any of its recommendations?
In your installation, do you use the FOG client? If so what is the check in time you set?