Issues Booting After Kernel Update in Qubes OS - Older Kernel Working

[apparatus]

Do you use NVIDIA in dom0?
If yes then see this:

Qubeos 4.2.3 fresh install stuck after entering successfully luks password

There seems to be a problem with NVIDIA and new kernels: Try to boot with nouveau.modeset=0 kernel command line option. If it’ll boot then you can try to install the older kernel 6.6.42 and use nouveau or try to install proprietary NVIDIA driver in dom0 instead of nouveau.