I also have been using a flip phone ever since I got a cell phone. I had to upgrade it once because the old phone only supports up to 3G network or whatever, and my carrier just silently dropped all calls on that network a few years back, so I had to upgrade to one with 4G. My current phone is Alcatel 4051S.

But I also have an Android phone without any data plan attached, which I use only for recording GPS coordinates when I am taking pictures outdoors. I have mostly managed to avoid places that require scanning some code or installing some app.