Hi.
I have only seen the issue if /boot ran out of space. In that case I had to uninstall a previous version of one of the installed kernels (which is not in use by the running system). Besides that I haven’t experienced it.
The reason why you dont see the cachyos kernel with that command is because “kernel” is the stock fedora kernel. If you add a * after it (dnf list installed kernel*), you should see all kernels which are installed at the moment.