@eso, I forgot to mention I chose swap file during install, which is hardcoded to create a 512M file on /swapfile (see https://codeberg.org/Calamares/calamares/issues/1722). I later replaced it with a file at least the size of my RAM to be able to hibernate.
But the point is not how to be able to hibernate, the point is dracut trying to guess if you need the resume module, which should be true if systemd is able to hibernate; the current guess being “if /sys/power/resume = 0:0 then hibernation is not enabled”, which is not accurate IMHO.