I have had that problem with many programs ever since I switched to a 4K monitor. I have to get closer to the screen to read the pop-up dialogue.
I can change the scale and resolution of the display and get modal pop-ups that are easier to read, but I lose some of the 4K resolution when I do that.
If I am interpreting your post correctly, this is a problem with the operating system, and is not specific to Audacity.