Oh after a system upgrade and reboot, that included an update of podman:
podman 2:2.1.1-12.fc33 -> 2:2.2.1-1.fc33
podman-plugins 2:2.1.1-12.fc33 -> 2:2.2.1-1.fc33
I now get a slightly different error message:
$ podman version
ERRO[0000] 'overlay' is not supported over extfs at "/var/home/rugk/.local/share/containers/storage/overlay"
Error: kernel does not support overlay fs: 'overlay' is not supported over extfs at "/var/home/rugk/.local/share/containers/storage/overlay": backing file system is unsupported for this graph driver
Note this still seems to be the default option.
Also funny, if I rerun this, I only get the error message (no ERRO[0000] is displayed anymore (which is useless anyway and I don’t even get what this tries to tell me TBH. Looks like the strange and useless error codes you know from Windows 
):
$ podman version
Error: kernel does not support overlay fs: 'overlay' is not supported over extfs at "/var/home/rugk/.local/share/containers/storage/overlay": backing file system is unsupported for this graph driver