Would like to use kexec for fast reboot and would like to have a clean shutdown before

Issue

• We try to use kexec for fast reboot and would like to have a clean shutdown (like with normal reboot) before.
• We would like to achieve something that allows us to decide if a normal reboot or a kexec reboot is performed. If we just load the kernel on with kexec -l on every boot, each reboot will be a kexec reboot.
• reboot should trigger a normal reboot and systemctl kexec-reboot should trigger a kexec reboot to the same kernel that is currently running.