The most recent working kernel (v. 6.13.8-1) in VBox is available here if you want to install it.
The reports here are based on OM package virtualbox-7.1.4-3 in Cooker host machine. Maybe people running VBox in other distros or Windows will see different results? That would be most helpful to know.
If some of you experience problem with this kernel in hardware then we may really have a bug.
I also noticed this same issue in QEMU/Virt Manager. I had the 6.12.9 iso downloaded from when I first installed OM, and that booted fine after install. I upgraded the VM and now it won’t boot.
Thanks @rugyada for that tip. Obviously I had not tried changing VBox settings, which is a good idea, maybe the first thing you should do, if you encounter difficulties.
There is a newer kernel 6.14.0-3 version in Cooker that seems to work with VBoxSVGA or VMSVGA set. ROME users can install that if they so desire. Heck Rock users can install that also.