This reminds me of the office worker who after having her monitor upgraded to higher quality high resolution model, quickly started to complain about all the font sizes in all the applications being too small. We tried all the tricks to increase the font sizes via Microsoft scaling setting to handle this but due to some custom apps that we used, it didn't work with all of them and she just hated smaller font sizes in general. We ended up giving her old monitor back which had the lower resolution and she was so happy to have her larger than life low res icons and fonts back again. Everyone else in the office was ok with the smaller fonts and higher resolution, just one person that didn't like it.
So the best way to increase the application font size and overall readability is to lower your resolution or go back to a lower native resolution monitor. With a nice video card you can have both.