@grammargirl last year I watched an 80 something relative on Android use some sort of enlargement window. After that I had to find it on iOS!
It will probably take some practice to manipulate this but iOS does have an analogous feature under Settings/Accessibility/Zoom (top switch to turn it on) I would set Zoom Region to “Window Zoom"
3 finger screen tap turns it on and off - tap and drag on the little handle to move it around, or just tap to change the magnification and other settings.