ghostcript can add a color profile, too. I use the regular ISO coated v2 (without the 300%). This is just a step to not do all things in Scribus by hand and make sure colors are not out of gamut.
I don’t now the command line from the top of my head. Just ping me again, so when I am on my computer I can send the complete ghostscript cli line that currently works for me.
The final profile is set up by Scribus, where I have set it to the ISO coated with 300%. Ideally I would like to have less steps in the chain, so that a change in the Inkscape-source involves less manually steps. One can dream of it. (:
For my my father I only have to make sure it looks not so different after each major upgrade. I have to be careful when there are new things, but apart from that he can do everything for himself except these major upgrades and backups.
So, he is happy with Fedora and Gnome classic.