Is it a fresh Qubes OS installation?
Or was it working before but broke after some update?
Did you try to boot Qubes OS with disabled qubes autostart?
Autostart troubleshooting | Qubes OS
What GPU do you use in dom0? Is it NVIDIA?
Enable log output during the Qubes OS boot to see the specific errors that you have like this:
Dom0 update freeze, system no longer boots - #5 by apparatus