Unless it isn't on the Pi for some reason, if you have a long-running script that you don't necessarily need to connect back to you can always nohup it.
Failed to start myscript.service: Unit myscript.service has a bad unit file setting.
See system logs and 'systemctl status myscript.service' for details.
I named my script my_script.py and copied and pasted from the website so there should be no spelling or syntax errors