[maccard]

You really don't want to turn off unity builds in unreal for anything larger than a toy project. The build system is "smart" (albeit itself is slower than say ninja). It breaks the project up into multiple unity "blobs" for you, and they're compiled in parallel. It also integrates with source control to remove files from the "working set" so if you're iterating on a small file it will be removed from the unity blob and compiled on its own for faster iteration.