I have mounted my NFS network shares using systemd. For every network path there is a *.automount and a *.mount unit.
The albums on this network shares are correctly set up in Digikam (not local, but network).

When a server containing an album is offline, digikam startup hangs indefinitely. Only starting the corresponding server (and making the network share available for automount) will make Digikam continue the startup.

Here the mnt-server.mount unit:

[Unit]
Description = Mount network shares on server.
Wants=cachefilesd.service
Requires=wake@server.service nfs-client.target
After=wake@server.service nfs-client.target
ConditionHost=!server

[Mount]
What=server:/
Where=/mnt/server/
Type=nfs
Options=fsc