Mounting an unreachable CIFS results in slow login and other problems

I have a NAS that I mount via CIFS. My /etc/fstab:

//192.168.178.1/FRITZ.NAS/ /home/xxx/NAS cifs credentials=/home\/xxx/.smbcredentials,vers=3.0,noserverino,uid=1000,\gid=1000,x-systemd.automount,x-systemd.requires=network-online.target,x-systemd.device-timeout=10ms 0 0

I works well in my home network, of course, but as soon as I leave the house and 192... isn't available anymore, I experience very slow logins and other problems, i.e. when trying to browse my files with Nautilus or any other program that tries to access the file system.

dmesg then shows:

[ 1176.653340] CIFS: Attempting to mount //192.168.178.1/FRITZ.NAS/[ 1186.984727] CIFS: VFS: Error connecting to socket. Aborting operation.[ 1186.984739] CIFS: VFS: cifs_mount failed w/return code = -2[ 1186.993225] CIFS: Attempting to mount //192.168.178.1/FRITZ.NAS/[ 1197.224579] CIFS: VFS: Error connecting to socket. Aborting operation.[ 1197.224590] CIFS: VFS: cifs_mount failed w/return code = -2[ 1197.233060] CIFS: Attempting to mount //192.168.178.1/FRITZ.NAS/[ 1207.464505] CIFS: VFS: Error connecting to socket. Aborting operation.[ 1207.464516] CIFS: VFS: cifs_mount failed w/return code = -2[ 1207.476803] CIFS: Attempting to mount //192.168.178.1/FRITZ.NAS/[ 1217.705176] CIFS: VFS: Error connecting to socket. Aborting operation.[ 1217.705187] CIFS: VFS: cifs_mount failed w/return code = -2[ 1217.713857] CIFS: Attempting to mount //192.168.178.1/FRITZ.NAS/

So over the course of dozens of seconds, it tries to mount the NAS again and again, which seems to block the system entirely...

The timeout option I added doesn't seem to help, dmesg tells me it is ignored:

[ 1078.414184] systemd-fstab-generator[532]: x-systemd.device-timeout ignored for //192.168.178.1/FRITZ.NAS/

Also adding a nofail option doesn't help.

Isn't there an option to have a very short timeout so it doesn't bother me when I'm not in my home network?