I’ve finally been successful:
While Electron seems to know the font “Latin Modern” (and Chrome does so as well), other tools like Inkscape and probably Rsvg do not recognize it. I had a look at the available fonts in Inkscape and noticed that “Latin Modern” cannot be selected. Instead, “CMU Serif” seemed to be the way to go. Choosing “CMU Serif” instead of “Latin Modern” while creating the plot lead to the pdf file containing the correct fonts.
Thank you very much !