I like the idea of a place where small and specific pieces of code can be added but I am afraid openplotter-serial is not that place. This serial app is in charge of making stable the system assignment of serial interfaces (udev rules) and making easier some connections between applications and serial sources. There are not any script running in the background connecting to sources and parsing data from them, actually if we do that, some connections will be busy and signal k and other apps will not be able to connect to them.
Being said this, I see a new app here. A place where you can easily add small pieces of code (snippets) that you can choose to run at startup or run at some point using the actions of the openplotter-notifications app. For example in your case you just have to set the serial devices in openplotter-serial, add these serial devices to your script, your script to an specific folder and choose to run them at startup in this new app.
Of course node-red is always a good option for snippets.
Being said this, I see a new app here. A place where you can easily add small pieces of code (snippets) that you can choose to run at startup or run at some point using the actions of the openplotter-notifications app. For example in your case you just have to set the serial devices in openplotter-serial, add these serial devices to your script, your script to an specific folder and choose to run them at startup in this new app.
Of course node-red is always a good option for snippets.