Packaged game looking sharper in Windowed / Windowed Fullscreen mode compare to Fullscreen mode?

Hi, I’m new to UE4.

My packaged game looks sharper in Windowed mode* (manually maximised to nearly fullscreen) *& Windowed Fullscreen mode compare to normal Fullscreen mode (looking slightly pixelated & blurry).

Widget texts in small font size are very pixelated in normal Fullscreen mode but sharp & readable in Windowed Fullscreen mode.

Is it normal or there’s some setting I’m not aware of that should be set?