If you cannot reduce the title bar to the desired size like 15 or 16 px, you need to reduce the title bar font.
It will also reduce window button size, so nothing else is required. Here, set the desired height of the title bar. Run it and go to Advanced appearance - Window Title Bars. If you want to reduce the title bar height and make window buttons smaller in Windows 10, here is how you can do it. Many users are not happy with the default appearance of window title bars in Windows It is too tall and the window caption buttons minimize, maximize, close are quite large.
