Hibernation suddenly stopped working on Linux Mint 22.3

Suddenly, since I recently rebooted, unfortunately systemctl hibernate stopped working. It configured it to work before, it's part of my daily workflow, but now it gives me this error:

$ systemctl hibernate
Call to Hibernate failed: Sleep verb 'hibernate' is not configured or configuration is not supported by kernel

I have enough SWAP, configured it correctly, and my kernel config supports it:

$ free -h      
               total        used        free      shared  buff/cache   available
Mem:            15Gi       4,3Gi       7,9Gi       1,0Gi       4,6Gi        11Gi
Swap:           19Gi          0B        19Gi
$ sudo swapon -s
Filename                Type        Size        Used        Priority
/dev/dm-2                               partition   20971516    0       -1
$ sudo cat /proc/cmdline
BOOT_IMAGE=/vmlinuz-7.0.0-31-generic root=/dev/mapper/vgmint-root ro quiet splash resume=/dev/dm-2
$ sudo grep HIBERN /boot/config-7.0.0-31-generic
CONFIG_ARCH_HIBERNATION_POSSIBLE=y
CONFIG_ARCH_HIBERNATION_HEADER=y
CONFIG_HIBERNATE_CALLBACKS=y
CONFIG_HIBERNATION=y
CONFIG_HIBERNATION_SNAPSHOT_DEV=y
CONFIG_HIBERNATION_COMP_LZO=y
# CONFIG_HIBERNATION_COMP_LZ4 is not set
CONFIG_HIBERNATION_DEF_COMP="lzo"

But indeed the kernel says hibernation is not supported:

$ cat /sys/power/state
freeze mem
$ cat /sys/power/disk
[disabled]

Online, I only found that the error typically comes from SecureBoot or zram being enabled, but this does not seem to be my problem:

$ sudo zramctl
$ sudo mokutil --sb-state
SecureBoot disabled

Any other ideas where I could look? Since that unfortunate reboot, I had the problem with both 6.14.0-37 and 7.0.0-31, no idea what could be the culprit. I don't know which kernel I was running before that unfortunate reboot.