You can apply the methods as below:
1. Resize the monitor with different scale and layout as step below:
-Right-click an empty spot on the desktop.
-Click "Display Settings".
-Note the current setting of the "Change size of..." and "Resolution".
-Choose the size and resolution.
-If the screen looks OK, click "Yes" to keep these display settings.
2. Resize Quartus front setting as steps below:
For your information, you can also change the Text Editor Fonts after open next template by clicking Tools>Options>Text Editor>Fonts
Can you try to update the driver as step below:
Step 1. Find the display driver under the Display adapters you used.
Step 2. Right-click on that graphics driver.
Step 3. Select Update.
Then Device Manager will perform the updates. Remember to restart your computer after the installation completes.
I just installed Quartus Prime Version 20.1.1 Build 720 11/11/2020 SJ Lite Edition and I am having a similar issue. Both the icon size (too small) and font size (too small or too large) are messed up out of the box for me. Notice in the background of the design the font on the counter object is huge, where as the text on the IP window is soo tiny I can't read it with a 24inch monitor. Similarly all the icons too small. Is there an easy fix for this?