It’s interesting, but I don’t think viewing order has to be chronological. If someone is adamant about watching everything, I’d recommend they go by production order.
This is true for pretty much any franchise. If you’re going to watch it all, you can’t go wrong with release order. That way you have the same context that original viewers did, and what the writers likely had in mind.
That doesn’t mean TOS the best starting point for newcomers, though, since they’re probably not committed to thousands of hours of Trek right out of the gate. They’re gonna bail if they don’t like the first few episodes they watch.