but it really doesn’t line up with a justifiable in-universe answer.

I went over to have a little look-see about Pon Farr on Memory Alpha.

"You only take a mate once every seven years?" "The seven-year cycle is biologically inherent in all Vulcans. At that time, the mating drive outweighs all other motivations." "And is there nothing that can disturb that cycle, Mister Spock?" "Extreme feminine beauty is always disturbing, madam." – Droxine and Spock, 2269 ("The Cloud Minders")

There's pretty much no justification for the biological reason behind the seven year cycle that I can remember. But do we know what cycle it is? Perhaps it's something to do with the planetary bodies around Vulcan? Like in humans, the menstrual cycle is about the same as one moon. (Sandi Toksvig once noted how it was definitely women who came up with the earliest calendars [in context they were talking about the "earliest man-made calendars"])

So if their planet had some sort of a cycle that every seven years there's a nice long summer because of some planetary alignment, it could be a good time for fighting and fucking.

Oh but I was just supposed to say "nice comment, thanks", and not babble on about something I was thinking about, lol.