How to add dependencies in RHEL systemd service configuration file using local or remote filesystems ?

Issue

• Why is RHEL system hung with systemd[]: Timed out waiting for device error at boot time ?
• Why is RHEL systemd service using a Filesystem device, not available in time ?
• Why is journaclctl showing systemd[]:Timed out waiting for device dev-mapper-VG\LV.device error messages ?
• Why are boot error messages seen similar to [Time] Timed out waiting for device dev-mapper-VG\LV.device ?
• How to add Filesystem dependencies in systemd Service configuration file, when a service requires remote Filesystems (FC / Network / FCoE) to be available ?
• Is there another way apart from using _netdev option in /etc/fstab to fix the systemd service requiring remote Filesystems to be available / mounted issue at boot ?
• Using Requires and After in systemd for service configuration file.