Something I noticed about the ARM builds is that getting/refreshing dnf repo metadata seems to be a major bottleneck: for some reason, the builds often get stuck for several minutes at a time each time the repo metadata is refreshed, and such metadata refreshes happen every time a new repository is added.

So, potentially one way to improve performance would be to consolidate the adding of new repositories so repo metadata only has to be refreshed once per build. I think that could be accomplished by ordering the BlueBuild modules so that all repo files are already in place before any dnf steps are run; the first steps in each recipe would just add repo files to /etc/yum.repos.d (or maybe could be part of a files step that adds other files, but in any case it shouldn't run dnf, and later dnf steps shouldn't add any new repositories).