A family of Microsoft word processing software products for creating web, email, and print documents.
After looking at the edits you made in your original message, I definitely see the difference between what you had earlier and what you have now regarding the user interface in Word. Based on the screen shots, the difference is clear but not gigantic.
Maybe a screen shot which shows your whole desktop with a few large (but not maximized) app windows would shed some light over what has happened. At least, such a screen shot would help us see the difference in sizes between the Office apps and one or two other, non-Office apps.
Generally, it isn't unusual that a combination of high resolution and a large display will make app windows too small, unless you change the scaling as well.