Thank you for contacting me! The month view supports the pinch gesture, i.e. you can make the whole view larger and scroll around by dragging two points of the screen with two fingers apart.
In addition you can increase the font size under "Settings > Display and Use > Month view > Font". Have you tried that? Doesn't that work? Did you maybe accidentally set "Maximal size when zooming" to a smaller value?
Please don't hesitate to contact me again if you have further questions!
Kind regards
Dominique Gunia