[robocat]

That analysis ignores the costs of breakage, theft, care plan, or insurance excess.

To get the best money for a second hand phone, you also need a good case (which is another sunken cost).

It can make sense, but pay attention to to other costs, because they add up.

I also do what the GP does: buy mid-range Android phones (Nokia at present, used to buy Moto), and give them to family and friends after a few years.

On topic: Nokia phones have a phone jack and have Android One (2 years version update, 3 years security, plus many more years of secure browsing).