Why don’t use the old fashioned way ? [HOWTO] build eOS in old fashioned way with breakfast -- now with interactive script
I have build my first roms in that way on an old i386 with 4 GB ram. It has needed a looooong time, but it was OK And this way is starting after a fail at that point where it fails and not at the beginning as docker do.
You have all sources available so you can start direct with
source build/envsetup.sh