So that almost worked, inasmuch as I used the nvm method to get the correct version of nodejs and the manual invocation all worked. As soon as I tried to run the systemd service as described it all failed (I couldn’t connect to the web server o9n the Rasp Pi). What I did was to change the plexamp.service file to use the nvm-specified version explicitly in the ExecStart statement, rather than the /usr/bin/node path: