you can merge the initrd + kernel into one signed binary pretty easily with systemd-boot
add luks root, then it's not that bad
add luks root, then it's not that bad
Then there is also `ukify` by systemd which also can create UKIs, which then can be installed with `kernel-install`, but that is a bit more work to set up than for `mkinitcpio`.
The main part is the signing, which I usually have `sbctl` handle.