The problem was, certain apps like my IDE phpStorm, would not use the actual resolution and degrades to lower resolution as if I have set my resolution to something less than optimal resolution of my screen. I have 1920×1080 screen on my laptop and the application would act like I have lower resolution so the app window will have blurred text and looks upscaled user interface.
Now the reason behind this seems to be, when we execute certain apps, it tries to scale the window if high DPI is detected, may be for better visibility, so all we need to do is disable this behaviour forcefully.
Steps to fix
Find the .exe file in the explorer (OR Start typing the app’s name in start menu and right click on the suggestion and click on “Open file location”).
Right click on .exe file. go to properties > Compatibility tab.
You’ll see an option that says “Disable display scaling on high DPI settings”. > check it to disable. Then click OK > open the app again. FIXED!