Monitor Math

My mother has a 21" iMac and is suffering from vision problems.
I currently have the resolution set to show text etc as large as possible (and I’m guessing its about 1.6x bigger). The problem is it reduces the amount of data available (icons etc)

The resolution of the iMac is 1920 x 1080
a 32" monitor would be 3840 x 2160 (double the iMac)

So. “assuming” the 32" monitor is 1.5x taller and setting the resolution to “big text” the same as the iMac is now, I should get 2x the amount of data (2160 / 1080), and it should be 2.4x larger (1.5 x 1.6)

Is that all correct? Does anyone have a 32" monitor and a 21" iMac they could test this with?

Sounds right, but you won’t gain any more real estate, or “data available”, it will still seem cluttered, just now it’ll be big and cluttered.

I would get a 27” 4K monitor. The text is really sharp and larger than normal. They can be had for $300 or so.