The error is clearly described
Add to your mount unit
[Install]
WantedBy=multi-user.target
In any case - if you enable the mount unit - it will override the automount unit.
When you use automount only enable the automount unit.
See the following articles in Tutorials
→ [root tip] [How To] Use systemd to mount ANY device
→ [root tip] [How To] systemd mount unit samples