@MindmeshLink the trivial systemd script fur daemons that are Just A Purrocess You Simply Run From The Command Line is

$ cat /etc/systemd/system/my-unit-name.service
[Unit]
Description=name of this service

[Install]
WantedBy=multi-user.target

[Service]
Type=simple
ExecStart=[command line here (you can use spaces)]

# the following make systemd automatically re-up the service every time it downs, which is usually desirable behavior
Restart=always
RestartSec=1 # you usually want some throttling in case it keeps exiting immediately

then run systemctl daemon-reload, and then systemctl enable my-unit-name.service (.service is optional). use systemctl status my-unit-name.service if you want confurmation that it worked fine.

standard output and error should automatically get logged to the systemd journal; you can view that output with journalctl -u my-unit-name.service

@MindmeshLink

• under the service section, WorkingDirectory=/path/to/desired/working/directory; if your script picks up configs from the current directory this will make setup simpler
• to run as a user who is not root, User=username, in the same section
• if needed, you can specify as many Environment="ENV_VAR=whatever" lines as required under that same section
• (you can also specify an environment file with EnvironmentFile=/path/to/file; the syntax is in VAR="contents" furmat)