This may be the issue. The current version of ZorinOS is based on Ubuntu 20.04 and runs on kernel 5.15, but the processor you are using was launched earlier this year. Generally, the newer the hardware the less support it will have in Linux.
According to this article only kernel 6.0 was tested:
I don't know if updating the kernel is the solution, or if this issue is something else entirely.
if you went backwards in bios versions from 8 to 6a that could prevent you from getting into the bios, if 6a doesn't support that cpu, try pushing f8 gain using the recovery methods usually the bios is put on a usb stick and placed in #1 usb port on the back and the mobo will auto update for gigabyte boards.
for the booting issue into Zorin, i agree with @zenzen its probably the kernel version, might have to wait later this year for zorin 17 to release, or if you feel adventurous, pull the ssd and place into another ryzen system install zornin update to kernel 6.x - (if you have broadcom wifi stay away from 6.2). shut down, place the ssd back into the pc, and try to boot, the kernel should properly detect the cpu. Also ryzens are super picky about ram, so make sure they are populated in the correct slots (a/a b/b) and try with and without xmp/amp profiles.