Running systemctl kexec results in the following error.
"Failed to open file system "/dev/nvme0n1p1": Permission denied".
Running with sudo instead results in "No boot loader entry suitable as default,
refusing to guess."

It works if you start the kexec-load service prior, so it seems there is an
issue with systemctl kexec not triggering services in the kexec.target.

A previous bug seems to have issues with /sbin/kexec-bootloader, but those
issues seem resolved. This finishes with the correct kernel loaded as shown by
kexec-bootloader -D returning images and showing a successful kexec call.
https://bugzilla.opensuse.org/show_bug.cgi?id=1153790