Ouch... you are correct about the GRUB entry. It should be GRUB_TIMEOUT and not GRUB_DEFAULT.

My eyes saw one thing and my fingers typed another.

I'll edit the post, and I'll include the suggestion on the GRUB_TIMEOUT_STYLE.

By the way, I have not seen this behavior with 22.04 or 23.04.. yet. I keep the VMs updated religiously for the most part, and currently am running 5.15.0-57-generic in my 22.04 VM, and version 5.19.0-21-generic in my 22.03 VM. Perhaps putting the kernel on hold on both would not be such a bad idea...