Regardless of font size. PS will automatically match the size of your computer screen. If you are not used to it, you want to change the old habit of full-screen display. Adjustment method:

On the menu bar: Edit-Preferences-Interface (note that the font size has not been adjusted), but the UI here is changed to 100% (general notebook or touch screen will automatically display 200%, or "automatic", you can turn back to 100%), and then close and restart.