Ubuntu 20.04 doesn't come back from hibernation, but restarts

When sudo systemctl hibernate is used, it seems to shut down the system, and when it is started again, the previous state is not there (e.g. no previously opened windows, it's like a fresh start).

I also tried sudo apt install hibernate and sudo hibernate, but it just seems to lock the screen at most without any hibernation.

My /etc/default/grub file has this line:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash resume=<SWAP_ID>"

And here is how my boot SSD drive (GPT system) is configured (output from sudo fdisk -l):

Device        Start       End   Sectors   Size Type
/dev/sdc1      2048    391167    389120   190M EFI System
/dev/sdc2    391168  68751359  68360192  32.6G Linux swap
/dev/sdc3  68751360 478908415 410157056 195.6G Linux filesystem

Secure boot is disabled from the BIOS.

In case it's relevant, I have 2 other drives /dev/sda (SSD) and /dev/sdb (HDD), but they are not used for any OS installation.

How do I get hibernate to work?