All I can offer is a dirty hack, so here you are …
Seems you have enough knowledge to be able to edit the files responsible for the contents and layout of the web display, which live in your core’s user folders - not sure, where that may be on a Linux machine, though
You could edit out the lines, responsible for displaying lyrics and be done, if you’re using just that one web display or never want to see lyrics on other web display devices.
See here.