Caching can help with a lot of builds, but the efficiency of the Build Cache depends on the size of the files you want to cache, as well as on the number of files you want to cache.
Alternatively, you can also turn off the “Clean build” setting in the workflow editor without causing issues. The first one will still have to do a clean build, because there’s no build cache at the time it runs but subsequent Xcode steps can use the build cache of the previous Xcode step(s), reducing the compilation time.
You can also submit your build using our support form, we would be happy to take a look!