If you have proxmox at home, play with docker in a VM, there are a great deal of docker images you can throw up and play with to help you understand. Once you get that down, play with building docker images to wrap your head around that, then best to copy the image that’s being used in your work infra if you need to make changes, then throw it up on another test VM to ensure you don’t break anything before pulling it into the live environment.
As for how the docker infra is setup, your explanation is pretty vague as far as what the images are doing, so nobody will really be able to tell you without that information - but my bet would be resources and/or segmentation