Just downloaded and briefly checked out Mathematica 13.
First reaction is that default magnification has changed quite a bit.
I am using Windows 10.
Consider changing ScreenResolutionCompatibilityMode parameter
ScreenResolutionCompatibilityMode
There is a general solution given in this Mathematica Stack Exchange discussion
Yes, setting magnification to 75% is a practical workaround.
But the Welcome Screen will still appear absurdly large.
Affirmative; the magnification is about 25% larger compared to the older version(s). Like Martijn, I had set the Global Magnification to 75% to get the familiar look back.
Yup noticed the same, I am now using global magnification 75% in preferences, which gives me the previous look, but not for the cell brackets.