I think you're right.
section9 must be referring to the "Four Years War," a feature of a FASA role-playing game which may have been mentioned as well in a Star Trek novel of the 1980s. Neither are canon and both contradict canon (not that canon can't contradict itself; it often does).
In fact, it's been suggested in a couple of movies/episodes that the Federation has been at peace for many decades, which is likely to be contradicted now by Discovery ("You helped start a war..."). Most of these are matters of inference rather than specifically stated.