iOS iCal font size
How can I increase the font size in iCal?
iPhone 8 Plus, iOS 14
You cannot change the font size for the individual Calendar app on your iPhone. What you can do is change the font size overall by opening Settings ➔ Display & Brightness ➔ Text Size : Here you can increase the size of the overall system Font and for the apps that support it. You may not like the overall change however there is no other option for the Calendar app.
Axel F.