That definitely doesn’t sound normal for a new ZZ502, especially only 4 miles in. Rocker arm nuts backing off and galling points to either improper initial preload, poor lubrication on startup, or a potential machining/parts quality issue with the valvetrain. GM Performance parts are usually decent, but defects or contamination during assembly/transport can still happen. The dust in the pan right away is
tangierscasinoonline also concerning, it could be residual manufacturing debris that should have been cleaned out before assembly. I’d stop running it, document everything, and contact the supplier or warranty support ASAP before further damage spreads through the cam and lifters.