Thanks @Smithers. Returning the machine is the only message Apple will understand or worry about. I know we're a small niche but It would be great if they at least acknowledged there is an issue with XCode and large ObjC projects. I'll have to wait for the next Mac Pro Pro or the Mac Serious Studio. Keeping the current Mac Studio for replying e-mails and spending twice as long to build our software is a tad expensive. The 500s it takes is more like 800s. Each file that xCode compiles takes about 3-4 seconds when it was about 0.1s-0.3s on an Intel machine. By the small number of posts I see here, I do not expect Apple feeling much pressure to address anything.

Submitted FB11935375 with this very same issue. Hopefully there will be a solution soon. Unfortunately, running a helper tool is not an option in our environment