missing AX200 firmware module iwlwifi-cc-a0-56.ucode in the sys-linux/linux-firmware packet error : Direct firmware load for iwlwifi-cc-a0-56.ucode failed with error -2 Please add this piece of software to the package. If this is added the problem is solved. See Gentoo forum https://forums.gentoo.org/viewtopic-t-1120801.html
As shown at https://git.kernel.org/pub/scm/linux/kernel/git/firmware/linux-firmware.git/tree/ this file does not yet exist upstream so Gentoo cannot package it. Intel Wifi is known to actively advance the allowable versions of firmware releases even before they are published. The message is normal and expected until it is released.
iwlwifi-cc-a0-56.ucode was not released at all, the next released fw is iwlwifi-cc-a0-59.ucode.