Man adds proper headphone jack to an iPhone that lacks one

Er, no; a 3.5mm jack IS an analog “headphone jack port” o.o’. As is a 1/4" jack, but it would be a bit silly to expect one on a phone, of course.

In other words, you need a Lightning jack-equipped pair of headphones, Lightning-to-3.5mm adapter and bog-standard cans, or a Bluetooth set. All work acceptably well (even Bluetooth, these days) BUT… If you want to charge your iCrap and use corded headphones at the same time, it gets a good bit more annoying and you’ll need more “techtopus” bits.