Recently I installed openSUSE Tumbleweed on my ThinkPad X390. Everything works so far, except Suspend to Disk. Sending it to hibernate looks good, but after I restart, it does not restore the old state but makes a fresh boot (unsaved files are gone, some applications are not there).
I have four partitions, one for uefi boot, one for the system (btrfs), one for /home (ext4), and swap (8 GiB). My computer has 8 GiB memory.
resume= parameter is missing on kernel command line. It is present in dracut stored command line, but systemd is not aware about it.
Add resume=... parameter referring to your swap partition, reboot, then try hibernate/resume again. I cannot tell you the value of this parameter because you did not provide information allowing to guess it. Better is to use UUID or LABEL, not device name.
You are right! I opened Yast Bootloader and added to the optional kernel parameter splash=silent quiet security=apparmor the resume command resume=ec326a00-0b02-4ab5-88e2-3f8291d6391aor resume=c171f784-9a31-4c24-ac6c-8300f1d5fca6.
In both cases the booting stopped with the error message a start job is running followed by the UUID. I waited for a couple of minutes and aborted.