xJC4Rx Please open DeviceConfig.log, in Documents > Electronic Arts > The Sims 4, copy the first 40 or so lines (stop at Options), and paste them here. You can delete your user and computer names, about 20 lines down; the file doesn't contain any other personal information.
For windowed mode, does it help to change the size, then quit and restart the game? The UI is supposed to be a certain number of pixels tall and wide, so shrinking the window shouldn't change its absolute size.
What do you mean about "but this mod"? If you're saying there's a mod to fix the UI size, it would be best to deal with the other problems first.