There's a difference between Zen3 desktop chips and Zen3 laptop chips. The former has 2 pieces of silicon and the later has 1. They just aren't shipping yet,

There's a difference between Zen3 desktop chips and Zen3 laptop chips. The former has 2 pieces of silicon and the later has 1. They just aren't shipping yet, apparently some announcements are due at CES in January, it's unclear if there will be volume available then. Much of AMD's current fab capacity is going for PS5 and Xbox X/S CPUs and of course the rather popular zen 3 desktops.