Hi @cjoejoe1
I believe you’re almost there. The only real issue is that you are using a command to clean cache. What that’s doing is clearing the build cache which means that every time you build, the build has to download all of your code and dependencies from scratch. With the cache, we only have to grab what has changed so it’s much faster.
Perhaps you already know that or perhaps you were thinking it was doing cache busting? You shouldn’t need to do any cache busting since part of the build process is to invalidate the cache on our edge network. This article might help explain better than I’m doing. 
I’d try pulling out the command that is clearing the cache and see if that improves your build performance and see how your CMS handles it.