First of all, up to the point answer on how to solve the issue.
You could list the installed kernels with sudo rpm -qa kernel\* | sort -V and remove the old ones or problematic ones with sudo dnf remove BAD_KERNEL. Regenerating grub menu entries should be automatic. But in case needed: grub2-mkconfig -o /boot/grub2/grub.cfg (on legacy boot systems, not EFI).
Second of all, of course, you should not need to do the above manually. The rpmspec should specify that the new kernels are replacing the old unsupported ones. So this is indeed a bug.
Third of all, some more background on the available Kernel options for Qubes OS.
- linux-kernel-latest (current stable v6.15 available for both r4.2 & r4.3).
- linux-kernel (current lts i.e. the default v6.12 available for both r4.2 & r4.3).
- linux-kernel-66 (old lts v6.6 only for r4.2)
- linux-kernel-61 (older lts v6.1 only for r4.2)
- linux-kernel-515 (ancient lts v5.15 only for r4.2)
The above diverse choices of Kernels are to suit everyone needs. For some people the latest kernel is what supports their hardware. For some other the lts one is what is more stable and what actually boots. But if you have any of the 3 last ones (after in-place upgrade), it should be safe to remove them from the system. It should be also noted that the above package names are for dom0 kernels. Name of the package for kernels installed at /var/lib/qubes/vm-kernels/* is different (something like kernel-qubes-vm*). And there are multiple choices for that too which might come handy for sys-net and sys-usb to support latest hardware.