I don't think there are any Macs that don't have a headphone jack, with the possible exception of the Mac Pro.

So much for the "people don't use headphone jacks anymore" argument for the phones.

The current model Mac Pro at least supports add-in PCIe cards. So you are only 1 sound card away from having as many headphone and other audio jacks that you want.

FWIW the current Mac Pro has a headphone jack.

It's at the top to the left of the USB-A ports.

https://www.apple.com/mac-pro/specs/

But (to be picky) why is it on the back???

I mean, if you're going to break with Apple tradition and have visible ports on the front, seems like you'd want the headphone jack to be one of them.

Probably because Studio/Professional Headphones come with long coords by default.

If there's one thing MacOS has taught us, it's that coords should be float, not long :)