Alternatively (or at least study of !) [HOWTO] build /e/ the (full) classic way (no docker, no scripts, just 'make') might be a learning experience.
Well that is what the guide says 
and both dumpling and kebab have been built and published by the team.
Does docker include the error.log in the logs directory ? This can be expected to point to the failure point; if the logs are kept and rotated, can you learn anything from the “history” ?
I learn a lot from a conky system monitor – or just htop in the background, but be aware that output might not fully reflect docker.
Maybe you have done it already but you might try an ordinary Lineage build.
Good luck.