Someone have the same problem and solution here
Enable Hibernation in openSUSE Tumbleweed (linux32bituefi.blogspot.com)
I am using default installation and dracut includes
resumemodule without any manual intervention and system performs resume (without LUKS).
Your right. you don’t need the resume module if you don’t use a encrypted swap. I’ve struggled with this 3 ou 4 month ago.
And I’m also remember that I have struggled with UUID (something was not intuitive beetween the physical partition and the logical crypted volume but in don’t remember what…). I don’t have anymore the laptop with this config so I can’t check where exactly was the trouble.
reading again the wiki, I’m asking myself if the problem was not in the UUID used in the grub menu command
Don’t forget to add the line
resume=UUID=....(using the UUID of the encrypted partition containing swap) to the bootloader kernel-paramter using Yast.