> how do you install packages/pull images
You pre-build the images with packages installed beforehand, then use those image offline.
You pre-build the images with packages installed beforehand, then use those image offline.
The fact that you haven't come across this kind of setup suggests that your hundreds of CI systems are not representative of the industry as a whole.
(I am familiar with Bazel, but I'll have to save the war stories for another thread. It's not a build tool we see our particular customers using.)