Further investigation reveals that in initramfs-5.3.6-200.fc30.x86_64.img there is no dm-crypt.ko module. But how come? How to fix it?
This module is in /lib/modules:
That did not solved the issue. But I now know what was the problem. Just a dracut unexpected, by me,
behavior.
I was running myself brewed kernel. Looks like dracut checks which kernel modules are
loaded on running system and includes the same in initramfs of specified kernel.
So, my kernel does not have dm-crypt module as it is compiled in the kernel.
That is why dracut did not included it in any initramfs I was building with my kernel running.