How to set the python environment for LaunchDaemons
I suggest that you use an absolute path in ProgramArguments, so

    &lt;key&gt;ProgramArguments&lt;/key&gt;
    &lt;array&gt;
    &lt;string&gt;python&lt;/string&gt;


would become

    &lt;key&gt;ProgramArguments&lt;/key&gt;
    &lt;array&gt;
    &lt;string&gt;/usr/local/bin/python3&lt;/string&gt;
    ..........


Your PATH variable is not correct. Change it to

    &lt;key&gt;PATH&lt;/key&gt;
    &lt;string&gt;/usr/local/bin:/usr/bin:/bin:/usr/sbin:/sbin&lt;/string&gt;